

JMlvvB 








Class 

Book 

Copyright N°_ 



COPYRIGHT DEPOSIT. 



PRACTICAL HAND BOOK 

of 

GAS, OIL AND STEAM 
ENGINES 

STATIONARY, MARINE, TRACTION 



GAS BURNERS, OIL BURNERS, ETC. 

FARM, TRACTION, AUTOMOBILE, LOCOMOTIVE 



A simple, practical and comprehensive book on the 
construction, operation and repair of all kinds of engines. 
Dealing with the various parts in detail and the various 
types of engines and also the use of different kinds of fuel. 

By 
JOHN B. RATHBUN, 

Consulting Gas Engineer, Editor " Ignition, " Instructor Chicago 
Technical College, Author Gas Engine Troubles and Installation. 



Published by 

CHARLES C. THOMPSON CO. 

CHICAGO, U. S. A. 



1-1* 



^1 



Copyright 1916 
CHARLES C. THOMPSON CO. 



Copyright MCMXIII 
CHARLES C. THOMPSON CO. 



Practical Hand Book Gas, Oil & Steam Engines 



4 



JUL 24 1916 
©CLA4 31988 



Table of Contents 



CHAPTER I— HEAT AND POWER 

Heat Energy — Mechanical Equivalent of Heat — Expansion Heat 
Units — Heat Engines — Efficiency — External and Internal 
Combustion Engines — Compression — Working Medium 5 

CHAPTER II— FUELS 

Calorific Values of Fuels — Solid, Liquid and Gaseous Fuels — 
Kerosene — Gasoline — Crude Oil — Producer Gas — Illuminating 
Gas — Coal — Benzol • 2~ 

CHAPTER III— WORKING CYCLES 

Definitions of Cycle — Four Stroke Cycle — Two Stroke Cycle — 
Two Port, Two Stroke— Three Port, Three Stroke— Revers- 
ing — Scavenging — Junker Two Stroke Cycle 58 

CHAPTER IV— INDICATOR DIAGRAMS 

Practical Use of the Indicator — Pressure Measurement — Reading 
the Card — Four Stroke Cycle Card — Defects in Practical 
Working— Two Stroke Cycle Card— Diesel Card— Effects of 
Mixture — Effects of Ignition 72 

CHAPTER V— TYPICAL FOUR STROKE CYCLE ENGINES 

Single Cylinder — Four Cylinder Automobile — Opposed Type — 
V Type — Tandem — Twin Tandem — Rotary Cylinder — Radial 
Diesel — Knight — Argyle — Rotary Valve . 87 

CHAPTER VI— TYPICAL TWO STROKE CYCLE ENGINES 

Two Port— Three Port— Marine— Controlled Port— Aeronautic— 
Oechehauser— Gnome Rotary Two Stroke, Koerting . .144 



TABLE OF CONTENTS 

CHAPTER VII— OIL ENGINES 

Elyria — Marine Diesel — Installation — Aspiration Types — Fair- 
banks Morse — Kerosene — Carburetion Diesel — Semi Diesel — 
Combustion of Heavy Oils 160 

CHAPTER VIII— IGNITION SYSTEMS 

Hot Tube System — Low Tension System — High Tension System 
— Details of Make and Break Batteries — Low Tension Mag- 
netos — High Tension Magnetos — Coils — Adjustment — 
Troubles 195 

CHAPTER IX— CARBURETORS 

Principles of Carburetion — Jet Carburetors — Water Jacketing — 
Fuel Supply — Different Types of Auto Carburetors — Adjust- 
ment Carburetor Troubles 271 

CHAPTER X— LUBRICATION 
Forced Feed — Splash System — Oil Pumps — Lubrication Troubles, .285 

CHAPTER XI— COOLING SYSTEMS 
Evaporation Systems — Radiators — Air Cooling 299 

CHAPTER XII— SPEED GOVERNORS 

Automobiles — Stationary — Adjustment — Mixture — Control — 
Hit and Miss — Mixed Systems • 308 

CHAPTER XIII— TRACTORS 
Gasoline and Oil Tractors — Mechanism of Various Types 324 

CHAPTER XIV 
Steam Tractors 349 

CHAPTER XV— OIL BURNERS 

Combustion — High Pressure System — Low Pressure System — 
Mixed System — Burners for Furnaces, Locomotives, etc 363 



Gas, Oil and Steam 
Engines 



CHAPTER I 
HEAT AND POWER 

(1) The Heat Engine. 

Heat engines, of which the steam engine and gas engine are 
the most prominent examples, are devices by which heat en- 
ergy is transformed into mechanical power or motion. In all 
heat engines, this transformation of energy is accomplished by 
that property of heat known as "expansion,'' by which an in- 
crease or decrease of temperature causes a corresponding in- 
crease or decrease in volume of the material subjected to the 
varying temperatures. The substance whose expansion and con- 
traction actuates the heat engine is known as the "working 
medium, and may be either a solid, liquid, or a gas. The extent 
to which the working medium is expanded depends not only 
upon the change of temperature but also on its composition. 

In all practical heat engines, the heat energy is developed 
by the process of combustion, which is a chemical combination 
of the oxygen of the air with certain substances, such as coal 
or gasoline, known as "fuels." The heat producing elements 
of the fuels are generally compounds of carbon and hydrogen, 
which when oxydized or burnt by the oxygen form products 
that are unlike either of the original components. It is due to 
this chemical change that heat energy is evolved, for the heat 
represents the energy expended by the sun in building up the 
fuel in its original form, and as energy can neither be created 
nor destroyed, heat energy is liberated when the fuel is de- 
composed. The heat energy thus liberated is applied to the 
expansion of the working medium to obtain its equivalent in the 
form of mechanical power. 



6 GAS, OIL AND STEAM ENGINES 

During the period of expansion, the heat obtained by the 
combustion is absorbed by the working medium in proportion 
to its increase in volume, and as this increase is proportional 
to the mechanical effort exerted by the engine, it will be seen 
that the output of the engine in work is a measure of the heat 
applied to the medium. The quantity of heat absorbed by the 
medium represents the energy required to set the molecules of 
the medium into their new positions in the greater volume, or 
to increase their paths of travel. In the conversion of heat, each 
heat unit applied to the medium results in the production of 
778 foot pounds of energy, providing that there are no heat or 
frictional losses. 

In explanation of these terms or units, we wish to say, that 
the unit of heat quantity, called the BRITISH THERMAL 
UNIT is the quantity of heat required to raise one pound of 
water, one degree Fahrenheit, and the FOOT POUND is the 
work required to raise one pound through the vertical distance 
of one foot. As the British Thermal Unit = 778 foot pounds 
it is equivalent to the work required to raise 778 pounds one 
foot or one pound 778 feet, or any other product of feet and 
pounds equal to the figure 778. 

As liquids expand more than solids with a given temperature, 
and gases more than either, the mechanical work returned for 
a given amount of thermal energy (the EFFICIENCY) will be 
greater with an engine using gas as a working medium than one 
using a solid or liquid working medium. The steam engine and 
the gas engine are both examples of heat engines using gaseous 
working mediums, the medium in the steam engine being water 
vapor and in the gas engine, air and the gaseous products of 
combustion. For this reason the working medium will be con- 
sidered as a gas in the succeeding chapters. 

Practically the only way of obtaining mechanical effort from 
an expanding gas is to enclose it in a cylinder (c) fitted with a 
freely sliding plunger or piston (p) as shown in Fig. 1. Two 
positions of the piston are shown, one at M indicated by the 
dotted lines, and one at N indicated by the full lines. It will" be 
assumed that the space between the cylinder head P and the 
piston at M represents the volume of the gas before it is 
heated and expanded, and that the volume between O and N 
represents the volume after heating and expansion have oc- 
curred. The vessel B represents a chamber containing air that 
is periodically heated by the lamp L, and which is connected 
to the working cylinder C by the pipe O. 



GAS, OIL AND STEAM ENGINES 



P M 




J?&&^ 



soo- 




1ST* 



r/js.3. 



Figs. 1-2-3. Showing Expansion in an External Combustion Engine, the 
Cycle of Operations in an Internal Combustion Engine, and the 
Pressure Diagram of the Latter Engine Giving the Pressures at 
Various Points in the Stroke. 



8 GAS, OIL AND STEAM ENGINES 

With the piston at M, the lamp L is lighted and placed under 
the retort B which results in the immediate expansion of the 
air in B. The expanded air passes through O into the cylinder, 
and if sufficient heat is supplied, exerts pressure against the 
piston since it occupies much more than its original volume. 
Providing that the friction of the device and the load on the 
shaft S are low enough the pressure on the piston will move it 
to the position N in the direction of the arrow, thus accom- 
plishing mechanical work. The motion of the piston revolves 
the crank to which it is connected by the rod X from D to E. 
During the trip from M to N the volume of gas has greatly 
increased being supplied continuously with heat from the lamp. 
As a considerable amount of heat has been radiated from the 
cylinder during the piston travel, and a considerable portion of 
the mechanical work lost through the friction of the piston on 
the cylinder walls, and by the crank, not all of the heat units 
are represented at the crank as mechanical effort. 

Because of the limiting length of the cylinder, and the tern-* 
perature limits of the lamp it is not possible to expand the 
working medium and increase the temperature indefinitely, there- 
fore there must be a point where the application of heat must 
cease and the temperature be reduced in order to bring the gas 
back to its original volume and the piston to its original position 
so that the expansion may be repeated. This condition results 
in a very considerable loss of heat and power in addition to the 
losses previously mentioned, as the heat taken from the medium 
to reduce it to its original volume is thrown away as far as the 
production of power is concerned. To return the piston to its 
former position without expending energy on the engine, the 
volume and pressure may be reduced either by allowing the gas 
to escape to the atmosphere by means of a valve, or by removing 
the lamp and cooling the air by the application of water, but in 
any case the heat of the air is lost and the efficiency of the en- 
gine reduced. 

To increase the efficiency of the engine and reduce the loss 
just mentioned, nearly all heat engines, either steam or gas, 
have the working medium at the highest temperature for only 
a small portion of the stroke, after which no heat is supplied 
to the cylinder. As the pressure forces the piston forward the 
volume increases, and as no more heat is supplied, both the 
pressure and the temperature continue to decrease until the end 
of the stroke is reached, thus utilizing the greater part of the 
heat in the expansion. Since the temperature at the end of the 



GAS, OIL AND STEAM ENGINES 9 

stroke is comparatively low, very little heat is rejected when the 
valve is opened for the return stroke. This loss would be the 
least when the temperature of the gas at the end of the stroke 
was equal to the temperature of the surrounding air. With 
both the internal and external temperatures equal, there would 
be no difference between the pressure of the gas in the cylinder 
and that of the surrounding air. 




Fig. l-a. Fairbanks-Morse Two Cylinder, Type "R E" Stationary Engine 
Direct Connected to a Dynamo. 

It will be seen from the. example just given that the heat 
engine performs mechanical work by dropping the working 
medium from a high to a low temperature, as it receives the 
medium at a high temperature from the lamp and rejects it at 
atmospheric temperature after delivering a small percentage of 
useful work. This may be compared to a water wheel- which 
receives the working medium (water) at a high pressure and 



10 GAS, OIL AND STEAM ENGINES 

rejects it at a lower pressure. Carrying this comparison still 
further, it is evident that an increase in the range of the work- 
ing temperatures (high and low) would increase the output oi 
the heat engine in the same way that an increase in the range 
of pressures would increase the output of the water wheel. The 
temperature at which the engine receives the working medium 
and the temperature at which it is rejected determines the num- 
ber of heat units that are available for conversion into mechan- 
ical energy, and therefore, if the range be increased by either 
raising the upper limit of temperature or by reducing the lower 
limit, or by the combined increase and decrease of the limits, 
the available heat will be increased. 

Based on the temperature range, the maximum possible ef- 
ficiency of the heat engine may be expressed by the ratio — 
Reception Temperature — Rejection Temperature 

E = 

Reception Temperature 

This maximum defined by Carnot establishes a limit that can 
be exceeded by no engine, whatever the construction or work- 
ing medium. 

According to the methods adopted in applying the heat of 
combustion to the working medium, heat engines are divided 
into two general classes, (1) External combustion engines, (2) 
Internal combustion engines. The expressions "Internal" or 
"External" refer to the point at which combustion takes place 
in regard to the working cylinder, thus an internal combustion 
engine is one in which the combustion takes place in the work- 
ing cylinder, and an external combustion engine is one in w r hich 
the combustion takes place outside of the working cylinder. 
The steam engine is an example of an external combustion en- 
gine, the fuel being burned in the furnace of a boiler which 
is independent of the engine cylinder proper. As the fuel is 
burned directly in the cylinder of a gas engine it is commonly 
known as an internal combustion engine. 

An external combustion engine, such as the steam engine is 
subject to many serious heat losses because of the indirect 
method by which the heat is supplied to the working cylinder, 
aside from the losses in the cylinder. Much of the heat goes 
up the smoke stack and much is radiated from the boiler set- 
tings and the steam pipes that lead to the engine. The greatest 
loss however is due to the fact that the range of temperatures 
in the working cylinder is very low compared to the temper- 
atures attained in the boiler furnace, for it is practically impos- 



GAS, OIL AND STEAM ENGINES 11 

sible to have a greater range than 350°F to 100°F with a steam 
engine, while the furnace temperatures may run up to 2500° F 
and even beyond. 

High temperatures with a steam engine result in the de- 
velopment of enormous pressures, a temperature of 547°F cor- 
responding to an absolute pressure of 1000 pounds per square 
inch. This pressure would require an extremely heavy and in- 
efficient engine because of the terrific strains set up in the mov- 
ing parts. The pressures established by air as a working me- 
dium are very much lower than those produced by air or any 
permanent gas at the same temperature, and for this reason it 
is possible to exceed a working temperature of over 3000°F 
in the cylinder of a gas engine without meeting with excessive 
pressures. This high working temperature is one of the reasons 
of the extremely high efficiency of the gas engine. 

In order to compete with the gas engine from the standpoint 
of efficiency, the steam engine builders have resorted to super- 
heating the steam after it has left the boiler in order to in- 
crease the temperature range* in the cylinder. By applying ad- 
ditional heat to the steam after it has passed out of contact with 
the water it is possible to obtain up to 600°F without material 
increase in the pressure, but the practical gains have not been 
great enough to approach the gas engine with its 3000°F. After 
reaching his maximum temperature at this comparatively low 
pressure, the steam engineer has still to eliminate a number of 
other losses that do not obtain with the gas engine. 

Since the radiation losses of a burning fuel are proportional 
to the time required for burning, it is evident that the rate of 
combustion has much to do with the efficient development of 
the heat contained in it, and it is true that rapid combustion 
develops more useful heat from a given fuel than slow. In the 
gas engine the combustion is practically instantaneous with a low 
radiation loss, but in the steam engine the rate is slow, and with 
the excess of air that must necessarily be supplied, a great part 
of the value of the fuel is lost before reaching the water in the 
boiler. The temperature of the medium determines the ef- 
ficiency of the engine and as rapid combustion increases the 
temperature it is evident that the gas engine again has the 
best of the problem. 

In the case of the gas engine where the fuel (in gaseous 
form) is drawn directly into the working cylinder in intimate 
contact with the working medium (air) and in the correct pro- 
portions for complete combustion, each particle of fuel, when 



12 



GAS, OIL AND STEAM ENGINES 



ignited, applies its heat to the adjacent particle of air instantly 
and increases its volume with a minimum loss by radiation. 

A gas engine is practically a steam engine with the furnace 
placed directly in the working cylinder with all intervening 
working mediums removed, the gases of combustion acting as 
the working medium. It derives its power from the instant- 
aneous combustion of a mixture of fuel and air in the cylinder, 
the expansion of which causes pressure on the piston. Under 
the influence of the pressure on the piston, the crank is turned 




Fig. l-b. The English Adams Automobile Motor (End View), Showing 
the Magneto Driven by Spiral Gears at Right Angles to the Crank- 
Shaft. 

through the connecting rod and delivers power to the belt 
wheel where it is available for driving machinery. Whether the 
fuel be of solid liquid, or gaseous origin it is always introduced 
into the cylinder in the form of a gas. 



(3) Combustion Jn the Cylinder. 

As the working medium in an internal combustion engine is 
in direct contact with the fuel it must not only be uninflammable 



GAS, OIL AND STEAM ENGINES 13 

but it must also be capable of sustaining combustion and must 
have a great expansion for a given temperature range. Since 
atmospheric air possesses all of these qualifications in addition to 
being present in all places in unlimited quantities it is natural 
that it should be used exclusively as the working medium for 
gas engines. Unlike the vapor working medium in a steam 
engine the medium in the gas engine not only acts in an 
expansive capacity but also as an oxydizing agent for burning 
the fuel, and therefore must bear a definite relation to the 
quantity of the fuel in the cylinder to insure complete com- 
bustion. 

In the gas engine the use of gaseous fuel is imperative since 
there must be no solid residue existing in the cylinder after 
combustion and also for the reason that the fuel must be in a 
very finely subdivided state in order that the combustion shall 
proceed with the greatest possible rapidity. In addition to the 
above requirements the introduction of a solid fuel into the 
cylinder would involve almost unsurmountable mechanical prob- 
lems in regard to fuel measurement for the varying loads on the 
engine. This limits the fuel to certain hydrocarbon or com- 
pounds of hydrogen and carbon in gaseous form of which the 
following are the most common examples: 

(a) CARBURETED AIR consisting of a mixture of atmos- 
pheric air and the vapor of some hydrocarbon (liquid) such as 
gasoline, kerosene or alcohol. 

(b) OIL GAS formed by the distillation of some heavy, non- 
volatile oil, or the distillation of tar or paraffine. 

(c) NATURAL GAS obtained from natural accumulations 
occurring in subterranean pockets in various parts of the 
country. 

(d) COAL GAS, made artificially by the distillation of coal, 
commonly called "illuminating" gas. 

(e) PRODUCER GAS, some times known as "fuel gas," pro- 
duced by the incomplete combustion of coal in a form of fur- 
nace called a "producer." 

(f) BLAST FURNACE GAS, the unconsumed gas from the 
furnaces used in smelting iron, somewhat similar to producer 
gas but lower in heat value. 

It should be noted that there is no essential difference be- 
tween engines using a permanent gas or an oil as in either case 
the fuel is sent into the cylinder in the form of a vapor. In 
the case of oil fuel, the vapor is formed by an appliance external 
to the engine proper. In this book, the heat action of an en- 



14 GAS, OIL AND STEAM ENGINES 

gine using one form of fuel applies equally to the engine using 
another. The selection of a particular fuel for use with a gas 
engine depends not only upon its value in producing heat, but 
also upon its cost, the ease with which it meets the peculiar con- 
ditions under which the engine is to work, and its accessibility. 

Neglecting for the moment, all of the items that do not affect 
the operation of the engine from a power producing standpoint, 
the principal requirement of a fuel is the production of a high 
temperature in the cylinder since the output is directly pro- 
portional to the temperature range. Since a very considerable 
mass of air is to be raised to this high temperature, the heat 
value, or CALORIFIC VALUE of the fuel in British Thermal 
units is of as much importance as the temperature attained in the 
combustion. The calorific value of different fuels vary widely 
when based either on the cubic foot or pound, and a considerable 
variation exists even among fuels of the same class owing to 
the different methods of production or to th-e natural conditions 
existing at the mine or well from which they originated. The 
principal elements of gas engine fuels, carbon and hydrogen, 
exist in many different combinations and proportions, and re- 
quire different quantities of air as oxygen for their combustion 
because of this difference in chemical structure. 

Since complete combustion is never obtained under practical 
working conditions, the actual evolution of heat and the actual 
temperatures are always much lower than those indicated by 
the CALORIMETER or heat measuring device. Besides the loss 
of heat due to imperfect combustion, there are many other losses 
such as the loss by radiation, connection, and slow burning, the 
latter being the principal cause of low combustion temperatures. 
From the statements in the foregoing paragraphs it will be seen 
that the theoretical or absolute calorific value of a fuel is not 
always a true index to its efficiency in the engine. 

Complete combustion results in the carbon of the fuel being 
reduced to carbon dioxide (C0 2 ) and the hydrogen to water 
(H 2 0), with the liberation of atmospheric nitrogen that was 
previously combined with the fuel, and some oxygen. The re- 
duction of the fuel to carbon dioxide and water produces every 
heat unit available since the latter compounds represent the 
lowest state to which the fuel can be burned. Carbon however 
may be burned to an intermediate state without the production 
of its entire calorific contents when there is not sufficient oxygen 
present to thoroughly consume the fuel. Incompletely con- 
sumed carbon produces a gas, carbon monoxide, as a product of 



(IAS, OIL AND STEAM ENGINES 



15 




Fig. F-2. Sunbeam Engine with Six Cylinders Cast "En Bloc" (in one 
piece). At the Right and Under the Exhaust Pipe is the Compressed 
Air Starting Motor that Starts the Motor Through the Gear Teeth 
Shown on Flywheel. From "Internal Combustion." 



16 GAS, OIL AND STEAM ENGINES 

combustion, and a quantity of solid carbon in a finely subdivided 
state known as "soot." Unlike the products of complete com- 
bustion, both the carbon monoxide and soot may be burned to 
a lower state with a production of additional heat when fur- 
nished with sufficient oxygen, both the soot and the monoxide 
being reduced to carbon dioxide during the process. 

As the soot and monoxide have a calorific value it is evident 
that much of the heat of the fuel is wasted if they are exhausted 
from the cylinder without further burning at the end of the 
stroke. To gain every possible heat unit it is necessary to fur- 
nish sufficient oxygen or air to reduce the fuel to its lowest 
state. As the free oxygen and nitrogen contained in the fuel 
are without fuel value, their rejection from the cylinder oc- 
casions no loss except for that heat which they take from the 
cylinder by virtue of their high temperature. 

With complete combustion the TEMPERATURE attained in- 
creases with the rate of burning, while the number of heat units 
developed remain the same with any rate of combustion. Be- 
cause of the conditions under which the fuel is burned in the gas 
engine the fuel is burned almost instantaneously with the result 
that high temperatures are reached with fuels of conparatively 
low calorific value. With a given gas the rate of combustion 
is increased with an increase in the temperature of the gas be- 
fore ignition and remains constant for all mixtures of this gas 
in the same proportion w T hen the initial temperature is the 
same. The rate of combustion also varies with the composition 
of the gas, hydrogen burning more rapidly than methane. As 
a rule it might be stated that the rate of burning decreases with 
the specific gravity of the gas, the light gases such as hydrogen 
burn with almost explosive rapidity, while the heavier gases 
such as carbon dioxide are incombustible or have a zero rate of 
combustion. In practice an increased rate of burning is ob- 
tained by heating the charge before ignition by a process that 
will be explained later. 

Another factor governing the output of an engine with a 
given size cylinder is the amount of air required to burn the 
fuel. The quantity of air necessary for the combustion of the 
fuel determines the amount of fuel that can be drawn into a 
given cylinder volume, and as we are dependent upon the fuel 
for the expansion it is evident that with two fuels of the same 
calorific value, the one requiring the least air will develop the 
most power. Since the air required to burn hydrogen gas is 
only one fourth of that required to burn the same amount of 



GAS, OIL AND STEAM ENGINES 17 

methane it is clear that more hydrogen can he burned in the 
cylinder than methane. This great increase in output due to 
the hydrogen charge is however, considerably offset by the 
greater calorific value of the methane. 

Should the air be in excess of that required for complete com- 
bustion, or should a great quantity of incombustible gas, such 
as nitrogen be present in the mixture, the fuel will be com- 
pletely burned, but the speed of burning will be reduced owing 
to the dilution. As the air is increased beyond the proper pro- 
portions the explosions become weaker and weaker as the gas 
becomes leaner until the engine stops entirely. Because of the 
fact that it is impossible in practice to so thoroughly mix the 
gas and air that each particle of gas is in contact with a particle 
of air, the volume of air used for the combustion is much greater 
than that theoretically required. A SLIGHT excess of air, mak- 
ing a lean mixture, increases the efficiency of combustion al- 
though it reduces the temperature and pressure attained in the 
cylinder. This is due to the fact that while the temperature of 
the mixture is lower than with the theoretical mixture the 
temperature of the burning gas itself is much higher. A mixture 
that is too lean to burn at ordinary temperatures will respond 
readily to the ignition spark if the temperature or pressure is 
raised. 

(4) Compression. 

In the practical gas engine the gas is not ignited at the be- 
gining of the suction stroke by which it is drawn into the 
cylinder, but is compressed in the front end of the cylinder by 
the return stroke of the piston, and then ignited. The process 
of compression adds greatly to the power output of a given 
sized cylinder and increases the efficiency of the fuel and ex- 
pansion. In order to understand the relation that the com- 
pression bears to the expansion let us refer to Fig. 2 in which 
C is the working cylinder, P the piston and G the crank. While 
the piston is moving towards the crank in the direction of the 
arrow A it draws the mixture, indicated by the marks xxxxx, 
into the cylinder, the quantity being proportional to the position 
of the piston. In this particular case let us assume that the 
area of the piston is 50 square inches and that the entire stroke 
(B) of the piston is 12 inches. To prevent confusion due to 
considerations of heat loss we will further assume that the 
cylinder is constructed of non-conducting material. 

With the piston at the position H, midway between J and I, 



18 GAS, OIL AND STEAM ENGINES 

the volume D is filled with the explosive mixture at atmospheric 
pressure and a temperature of 500° absolute. Since D = 6 inches 
and the area of the piston is 50 square inches, the volume D is 
equal to 6x50 = 300 cubic inches, and the entire volume is 
2x300 == 600 cubic inches. On igniting this mixture (at atmos- 
pheric pressure) the temperature will rise immediately, say to 
1000°F with the piston at H. According to a law governing the 
expansion of gases, known as Gay-Lussac's Law, the expansion 
vXT 
= V, where v == the initial volume of the gas before 

t 
ignition = 300 cubic inches; t =: the temperature before ignition 
500° absolute; V =s the volume of the gas after expansion; and 
T == temperature after ignition =s 1000° absolute. Inserting the 
values in numerical form we have as the final volume: — 
300 X 1000 

== 600 cubic inches == the volume after expansion, or 

500 
twice the original volume of gas. This means that the expan- 
sion is capable of driving the piston from H to I before the 
pressure is reduced again to atmospheric pressure. As the 
volume is expanded to twice that of the original volume at 
atmospheric pressure (14.7 pounds per square inch), the pres- 
sure against the piston before it starts moving will be 2 X 14.7 = 
29.4 pounds per square inch. 

Let us now consider the case in which the charge is com- 
pressed before ignition occurs and compare the expansion 
and pressure established with that produced by ignition at 
atmospheric pressure. To produce the compression the pis- 
ton will travel through the entire stroke to the position I on 
the suction stroke filling the entire cylinder volumes of 600 cubic 
inches with the mixture. On the return stroke the piston stops 
at H, reducing the original volume of 600 cubic inches to 300 
cubic inches, doubling the pressure of the gas. The initial and 
final temperatures will be considered as being the same as those 
in the first example, 500° and 1000°. From Gay-Lussac's Law — 
vXT 
= V and substituting the numerical values 

t 
600 X 1000 

= 1200 cubic inches, or the expanded volume will be 

500 
four times the compressed volume, or four times the initial 



GAS, OIL AND STEAM ENGINES 19 

volume of the first case where the gas was ignited at atmos- 
pheric pressure. 

It should be noted however, that while the expansion has 
been greatly increased by the compression, that this is not all 
gain, as equivalent work has been expended in compressing the 
charge. With the exception of doubling the fuel taken into the 
cylinder, and consequently doubling the output for a certain 
cylinder capacity, there has been no increase in fuel efficiency 
except that due to conditions other than the mere reduction in 
volume. In the second case the volume was increased four 
fold which resulted in a piston pressure of 4 X 14.7 = 58.8 pounds 
per square inch before the piston increased the volume by mov- 
ing from H. to I. 

The work done by the engine on the charge in compressing 
is converted into heat energy causing a rise in the temperature 
of the gas. This would not be a loss as it would reappear as 
mechanical energy on the return stroke of the piston through 
its expanding effect on the gas. This heat would, in effect, be 
added to the temperature due to ignition, and the sum would 
produce its equivalent expansion. The temperature due to the 
combustion may be determined by reversing Gay-Lussac's Law — 
t I Pt 

— = — or T = — 
p P p 

Where t = initial temperature; T = temperature combustion; 
P = pressure after combustion; p ■=. pressure before combustion. 
Because of the fact that the act of compressing the charge in 
the cylinder before ignition increases the temperature of the 
working medium, the compression will increase the speed of 
combustion and efficiency of the fuel as the rate of combustion 
increases with the initial temperature. This increased temper- 
ature due to initial compression of course results in a greater 
temperature range and output due to the increased rate of burn- 
ing, and this rate of combustion may be varied for different 
fuels by, changing the compression pressure. In a previous 
paragraph it was explained that the fuel efficiency was increased 
by a slight dilution or excess of air, and that while the temper- 
ature and pressure of the mixture were reduced by the dilution 
the temperature of the fuel was increased, provided that the 
inflammability was not decreased. 

Compression affords a means of using dilute mixtures without 
loss of inflammability, as the heat gained by the compression 
restores the inflammability lost by the effects of dilution. In- 



20 GAS, OIL AND STEAM ENGINES 

creased compression pressures increases the possible range of 
dilution, so that extremely lean gases and mixtures may be 
used with success with appropriately high compression. As an 
example of this fact we can refer to the engine using blast fur- 
nace gas, a fuel that is so lean that it cannot be ignited under 
atmospheric pressure. By increasing the piston speed, the heat 
of the compression can be made more effective as the gas lies 
in contact with the cylinder walls for a shorter time which of 
course reduces the heat to the jacket water. 

(5) Efficiency and Heat Losses. 

Up to the present time we have considered an engine in 
which there is no heat loss or loss from friction, but in the 
actual engine such losses are large and tend to materially re- 
duce the values of heat and pressure to be obtained from a 
fuel with a given calorific content. Applying the rule for heat 
engines given in a previous section where the efficiency is — 

f— t 

E = 

T 

We have the theoretical efficiency of a gas engine, neglecting 
friction, loss to the cylinder walls, and loss through the rejec- 
tion of heat with the exhaust gas, equal to — 
1960 — 520 

jr — — = 73.5 percent. 

1960 

In substituting the numerical, values in the above calculation 
it was assumed that the temperature of the burning mixture 
would be 1500° F above zero, and that the exhaust temperature 
would be as low as 60. Since the calculation is made from 
absolute zero, which is 460° below the zero marked on 
our thermometers, the temperature of the burning charge, 
T = 1500 + 460° = 1960° above absolute zero. Similarly the 
absolute temperature of the exhaust would be, t = 60 -f- 460 = 
520° absolute. The application of the absolute temperatures will 
be seen from the calculation for efficiency. The value given, 
73.5 per cent, it should be understood is the theoretical efficiency 
and is at least 20 per cent above the best results obtained in 
practice. The best record that we have had to date, is that 
established by a Diesel engine which returned 48.2 per cent of 
the Caroline value of the fuel in the form of mechanical energy. 
In order that the reader may have some idea of the losses that 
occur in the engine, and their extent we submit the following 



GAS, OIL AND STEAM ENGINES 



21 



table. These are the results of actual tests obtained from dif- 
ferent sources and represent engines built for different services 
and of various capacities: 



Losses-— Data 


Automobile 
Motor 


Stationary 
Engine 


Stationary 
Engine 




Horse-power 


3o- 

35. 8# 
24.6% 
8.6% 

15-4% 

Gasoline 


200 

31-0% 
30.0% 

6.5% 

8.2 

24-3 


1000 
2970 B.T.U. 
2835 B.T.U. 

810 B.T.U. 

540 B.T.U. 
2700 B.T.U. 

Producer Gas 




Heat lost to jacket water .... 
Heat lost in exhaust 


j Loss at per 




^Horse-power 


Heat lost by radiation 

Heat available as power 

Efficiency (per cent) 

Fuel 


in B.T.U.'s 







The remarkable efficiency of the Diesel engine is due prin- 
cipally to the extremely high compression pressure, which was 
from 500 to 600 pounds per square inch. When this is com- 
pared to the 60 to 70 pounds compression pressure used with 
automobile engines it is easy to see where the Diesel gains its 
efficiency. It is evident that as much depends on the manner 
in which the fuel is used in the engine as on the calorific value 
of the fuel. 

(6) Expansion of the Charge. 

When an explosive mixture is ignited in the cylinder with 
the piston fixed in one position thus making the volume con- 
stant, the increase of temperature is accompanied by an in- 
crease of pressure. If the piston is now allowed to move forward 
increasing the volume, the increase of volume decreases the 
pressure. Since in the operation of the gas engine the piston 
continuously expands the volume on the working stroke it is 
evident that there is no point in the stroke where the pres- 
sures are equal, and that the pressure is the least at the end 
of the stroke, it being understood of course that no additional 
heat is supplied to the medium after the piston begins its stroke. 

This distribution of pressure in the cylinder in relation to the 
piston position is best represented graphically by means of a 
diagram as shown by Fig. 3, in which K is the cylinder and P 
the piston. Above the cylinder is shown the diagram HGDE 
the length of which (HE) is equal to the stroke of the piston 
shown by (BC). Intersecting the line HI are vertical lines, A, 
a, b, c, C, which represent certain positions of the piston in its 
stroke. The height of the diagram H G represents to scale the 



22 GAS, OIL AND STEAM ENGINES 

maximum explosion pressure in pounds per square inch, and 
the line HG is drawn immediately above the piston position B 
which is at the inner end of the stroke. To the left of the 
line HS is drawn a scale of pressures ML divided in pounds per 
square inch so that the pressures may read off of the pressure 
curve GD. The line JI represents atmospheric pressure, and 
the divisions on ML, of course, begin from this line and in- 
crease as we go up the column. As an example in the use of 
the scale we find that the point F is at 50 pounds pressure above 
the atmospheric line JI. 

We will consider that the clearance space AB is full of mix- 
ture at the point B, and that it is moved toward the left to the 
point C filling the space AC full of mixture at atmospheric 
pressure. The location of the piston on the diagram is shown 
by D and E. The opening through which the gas was 
supplied to the cylinder is now closed, and the piston starts 
on its compression stroke, moving from C to A. As the 
volume is reduced from AC to AB, there is an increase 
of pressure which is shown graphically by the rising line EF. 
This line rises gradually from the line JI in proportion to the 
reduction in volume until the piston reaches the end of the 
compression stroke at B, at which point the compression is at 
a maximum. The extent of this pressure is shown by the 
length of HF which on referring to the scale of pressure at the 
left will be found to be 50 pounds per square inch. 

Ignition now occurs and the pressure increases instantly from 
the compression pressure at F to the maximum pressure at G 
which on referring to the scale will be found to equal 200 pounds. 
The actual increase of pressure due to ignition above the com- 
pression pressure will be shown by the length of the line 
FG which is equal to 150 pounds. As the pressure is now es- 
tablished against the piston it will begin to move forward with 
an increase of volume and a corresponding decrease in pres- 
sure, until it reaches the point C. This point at the end of the 
stroke is indicated on the diagram by D which by reference to 
the scale will be found equal to 25 pounds above atmosphere. 
An exhaust valve is now opened allowing the gas to escape to 
the atmosphere which reduces the pressure instantly from D to 
E on the atmospheric line. Expansion along the line GD is 
not complete as the pressure is not decreased to atmospheric 
pressure in the cylinder which means that there is a consider- 
able loss of heat in the exhaust. In practice the expansion is 



GAS, OIL AND STEAM ENGINES 



23 



never complete, but ends considerably above atmospheric pres- 
sure as shown. 

Complete expansion is shown by the dotted line GE which 
terminates at E on the atmospheric line. By following the 
vertical lines up from the points a, b, c, and d, the pressures 
corresponding to these piston positions can be found by measur- 




Fig. F-3. m Front Elevation of Curtiss "V" Type Aeronautical Motor. 
This is the Front View of the Motor Shown in the Frontispiece. 
See Chapter V for Description of this Type of Motor. 

ing the distance of the curve from the atmospheric line, on the 
given lines a, b, c or d. To find the pressure at the position a, 
for instance, follow upwards along the line a to the point c on 
the curve, the length of the line ef from the curve to the at- 
mospheric represents the pressure, which by reference to the 
scale ML will be found equal to 125 pounds. The pressure at 



24 GAS, OIL AND STEAM ENGINES 

any other point can be found in a like manner. Compression 
pressures may be found at any point by measuring from the 
atmospheric line to the compression curve FE along the given 
line. It will be noted that the combustion is so quick that the 
pressure rises in a straight line along GH, indicating that com- 
bustion was complete before the piston had time to start on 
the outward stroke. The expansion curves GE and GD are 
similar to the compression curve FE. With the actual engine 
the shape of the ideal card as shown by Fig. 3 is sometimes 
considerably deformed owing to the effects of defective valves, 
leaks, or improperly timed ignition. 

Pressure curves of actual engines are of the greatest value as 
they show the conditions within the cylinder at a glance and 
make it possible to detect losses due to leaks, poor valve set- 
tings, etc. These curves are traced by means of the INDICATOR 
which is an instrument consisting of a small cylinder which is 
connected to the cylinder of the engine, and an oscillating drum 
that is driven to and fro by the engine piston. The piston in 
the indicator cylinder is provided with a spring that governs 
its movements and communicates its motion to a recording 
pencil through a system of levers. The spring is of such 
strength that a pressure of so many pounds per square inch in 
the cylinder causes the pencil to draw a line of a definite length, 
this line being equivalent to the pressure line GH in Fig. 3. 
A piece of paper is wrapped about the indicator drum, and the 
drum is attached to the piston in such a manner that it turns a 
certain amount for every piston position, the complete stroke of 
the piston turning the drum through about three-quarters of 
a revolution. Rotation of the drum traces the horizontal lines 
of the diagram and the movement of the piston draws the 
vertical lines, so the combined movements of the drum and 
piston records the pressures and piston positions as shown by 
Fig. 3. 

Since the movement of the indicator piston represents the 
pressures in the cylinder to scale it is possible to compute the 
power developed in the cylinder as the output in mechanical 
units is equal to the product of the average force acting on the 
piston multiplied by the speed of the piston in feet per minute. 
This product of the force and velocity (known as "foot pounds 
per minute") divided by 33,000 (one horse-power = 33,000 foot 
pounds) gives the output of the engine in horse-power. 

As the pressure on the piston fluctuates throughout the 
stroke, it would be wrong to consider the force, in the calcula- 



GAS, OIL AND STEAM ENGINES 25 

ticn for power as being equal to the explosion pressure, and 
so the effective pressure is taken as being the average of all the 
pressures from the point of explosion to the exhaust The 
average pressure or "mean effective pressure" as it is called is 
computed from the indicator diagram by dividing it into a num- 
ber of equal parts along the horizontal line, adding the lengths 
of the pressure lines such as CH, CF, etc., and dividing the total 
length by the number of the lines. After the average height 
of the diagram is thus determined, the average length is mul- 
tiplied by the scale of the indicator or the pressure that is 
shown by it per inch. 




Fairbanks-Morse Gasoline Pumping Engine. Pump is Gear Driven From 
the Engine Crank-Shaft at Reduced Speed. 

Knowing the mean effective pressure, the total pressure on 
the piston, or the force is found by multiplying the area of the 
piston in square inches by the average pressure per square inch. 
This product is multiplied by the piston speed in feet per min- 
ute and is divided by the product of the number of strokes to 
the explosion and the quantity 33,000. Should there be more 
than one cylinder the result is multiplied by the number of 



26 GAS, OIL AND STEAM ENGINES 

cylinders, and this is multiplied by 2 in the case of a double 
acting engine. Stated as a formula this rule becomes: 

AXPX2RXLXNXO 
H.P.= 

33000 X C 

When A = Area of piston in square inches. 

P = Average or mean effective pressure per square 
inch. About 75 pounds for Gasoline Engines. 
See Table on Page 31. 

R = Revolutions per minute. 

L = Stroke of piston in feet. 

N = Number of cylinders. 

O = 2 when engine is double acting, that is when ex- 
plosions occur on both sides of the piston. 

C= Number of strokes per explosion. C = 4 in a four 
cycle engine, and 2 in a two cycle. 

It should be specially noted that the area of the piston is 
given in square inches and the stroke of the piston in feet. The 
number of revolutions per minute, R, i's multiplied by two in 
order to obtain the number of strokes, as there are two strokes 
per revolution. When the engine governs its speed by dropping 
explosions to meet varying loads, the quantity C should be 
omitted and the explosions counted, 

Due to the fact that the incoming charge of the mixture is 
expanded by the heat of the passages, a full charge computed 
at atmospheric temperature is never obtained in the cylinder 
and for this reason the gas should be kept as cold as possible 
before entering the passages in order to obtain the maximum 
output. Friction due to restricted passages and valve openings 
also reduces the amount of mixture available. Small exhaust 
valves and pipes prevent the gases from escaping freely to the 
atmosphere and produces a back pressure on the piston which 
cuts down the effective pressures. All of these items are re- 
corded by the indicator and makes it possible to make altera- 
tions that well increase the output of the engine. 

Because of the reduced atmospheric pressures at high altitudes 
the output and compression are reduced for every foot of ele- 
vation above sea level. As the weight of the atmosphere is 
reduced, less mixture is drawn into the cylinder. Taking the 
output of the engine as 100 per cent at sea level, it is reduced 
to less than 62 per cent at an elevation of 15,000 feet. 



CHAPTER II 
FUELS AND COMBUSTION 

(7) Combustion. 

The phenomenon called combustion by which we obtain the 
heat energy necessary for the operation of the internal combus- 
tion engine is a chemical combination of the air with the fuel. 
This process results in heat and some light which is equal in 
quantity to the energy required to separate the fuel compound 
into its elements or to build it up in its present form from the 
original elements. If the process is comparatively slow, the 
compound is called a fuel, if it is instantaneous it is called an 
explosive. Some substances produce mechanical force through 
an instant, without the evolution of much heat, due to the dis- 
integration of an unstable compound. The effect of the latter 
type of which dynamite is an example is static, that is to say, 
it is not capable of producing power, but only pressure. For 
this reason, compounds having an instantaneous effect without 
the ability to produce the pressure through a distance, or an 
expansion, are not considered as suitable fuels for a heat engine. 

A fuel is essentially a substance which is capable of generat- 
ing heat, which is a form of energy, and not static pressure. The 
heat engine is instrument which transforms this energy into 
power which is again dissipated into heat through the friction 
of the engine itself and by the load that it drives. This is an 
illustration of the physical law that "energy can neither be 
created nor destroyed," that is, the heat energy developed by 
the fuel is converted into mechanical energy which is again 
transformed into heat energy through friction. 

It should be understood that fuel belongs to that class of 
substances that will not burn nor evolve energy under any 
temperature, pressure, or shock, without an outside supply of 
oxygen. This is the characteristic property of all fuels used 
with the infernal combustion engine. Each element, such as 
carbon and hydrogen, in a compound fuel, develops a certain 
definite amount of heat during their complete combustion, and 
at the close of the process certain compounds are formed that 

27 



28 



GAS, OIL AND STEAM ENGINES 



represent the lowest chemical form of the compound. To re- 
store the products of combustion to their original form as fuel 
would require an expenditure of energy equal to that given out 
in the combustion. 

While all substances that are capable of oxydization or com- 
bustion can be made to liberate heat energy, it does not follow 
that all of them can be successfully used as fuels. A fuel suit- 
able for the production of power must be cheap, accessible and 
of small bulk, and must burn rapidly. Such fuels must also be 
products of nature that require no expenditure of energy in 
their preparation or completion. 





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Fairbanks-Morse Producer Plant and Engine, 
Operation, 



Connected for 



In practical work, the natural fuels are coal, mineral oils, 
natural gas, and wood, which are compounds of the elements 
carbon and hydrogen. When these fuels are burned to their 
lowest forms the products of combustion consist of carbon 
dioxide and water, the first being the result of the oxydization 
of carbon, and the latter a compound of oxygen and hydrogen. 
In solid fuels, such as coal, a portion of the compound consists 
of free carbon and the remainder of a compound of carbon and 
hydrogen known as a HYDROCARBON. In liquid fuels there 
is little, if any, free carbon, the greater proportion being in the 



GAS, OIL AND STEAM ENGINES 29 

form of a hydrocarbon compound. Natural gas is a hydrocarbon 
compound. 

It should be noted that a definite amount of oxygen is re- 
quired for the complete combustion of the fuel elements, and 
that a smaller amount of oxygen than that called for by the 
fuel element results in incomplete combustion, which produces 
a product of higher form than that produced by the complete 
reduction. The product of incomplete combustion represents a 
smaller evolution of heat than that of the complete process, 
but if reburned in a fresh supply of oxygen the sum of the 
second combustion together with that of the first will equal the 
heat of the complete oxydization. When pure carbon is uncom- 
pletely burned the product is carbon monoxide (CO) instead of 
carbon dioxide (C0 2 ). 

Carbon completely burned to carbon dioxide produces 14,500 
British thermal units per pound of carbon, while the incom- 
plete combustion to carbon monoxide evolves only 4,452 British 
thermal units, or less than one-third of the heat produced 
by the complete combustion. Theoretically one pound of car- 
bon requires 2.66 pounds of oxygen to burn it to carbon dioxide. 
On supplying additional oxygen, the carbon monoxide may be 
burned to carbon dioxide and the remainder of the heat may 
be recovered, or 10,048 British thermal units. When a hydro- 
carbon, either solid, liquid or gaseous is burned with insufficient 
oxygen, solid carbon is precipitated together with lower hydro- 
carbons, and tar. In an internal combustion engine the pre- 
cipitated solid carbon is evident in the form of smoke. 

Since the carbon and hydrogen elements of a fuel exist in 
many different proportions and conditions in coal and oil, differ- 
ent amounts of oxygen are required for the consumption of dif- 
ferent fuels. It should also be borne in mind that a greater 
quantity of air is required for the combustion of a fuel than 
oxygen, as the air is greatly diluted by an inert gas, nitrogen, 
which will not support combustion. Because of the impos- 
sibility of obtaining perfectly homogenous mixtures of air and 
the fuel, a greater quantity of air is used in practice than is 
theoretically required. 

In a steam engine the fuel can be used in any form, solid, 
liquid, or gaseous, but in an internal combustion, it must be 
in the form of a gas no matter what may have been the form 
of the primary fuel. Fortunately there is no fuel which may 
not be transformed into a gas by some process if not already 
in a gaseous state. The petroleum products are vaporized by 



30 GAS, OIL AND STEAM ENGINES 

either the heat of the atmosphere or by spraying them on a 
hot surface. Coal is converted into a gas by distilling it in a 
retort or by incomplete combustion. The heat energy developed 
by a gas when burning in the open air depends on its chemical 
combustion, but its mechanical equivalent in power when 
burned in the cylinder of the engine depends not only upon 
its composition but upon the conditions under which it is 
burned as stated in the chapter devoted to the subject of heat 
engines. 

(8) Gaseous Fuels. 

While the calorific values of the different gases given in 
the accompanying table are approximately correct for gases 
burning in the open air at atmospheric pressure they develop 
widely different values in the cylinder of an engine because of 
the effects of compression and preheating. The table serves, 
however, as an index to the relative values of the fuels under 
ordinary conditions without compression. While natural gas 
has nearly eight times the calorific value of producer gas in 
the open air, its actual heat value in the cylinder is only about 
45 per cent greater. While acetylene has an exceedingly high 
calorific value and explodes five times as fast as gasoline gas, 
it develops only 20 per cent more power in the same cylinder. 
Another item affecting the value of a gas is the rate at which 
it burns, which is in part a characteristic of the fuel and partly 
a factor of the conditions under which it is burnt. This sub- 
ject is treated of in the chapter devoted to the heat engine. 

The calorific value of a gas may either be computed from its 
chemical composition or by burning it in an instrument known 
as a calorimeter. A gas calorimeter consists of a small boiler 
or heating tank which is carefully covered with some non- 
conducting material so as to prevent a loss of heat to the at- 
mosphere. The gas under test is burned in the boiler whose 
extended surface catches as much of the heat as possible and 
transfers it to the water in the boiler. The weight of the 
water heated and its temperature are taken when a certain 
amount of the gas has been burned (say 100 cubic feet), and 
from this data, the heat units per cubic foot of gas are com- 
puted. 

As a British thermal unit is the amount of heat required 
to raise the temperature of one pound of water through one 
Fahrenheit degree (at about 39.1° F.), the total heat per cubic 
foot of gas as observed by the calorimeter is equal to the weight 



GAS, OIL AND STEAM ENGINES 



31 



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32 GAS, OIL AND STEAM ENGINES 

of the water multiplied by its use in temperature in degrees, 
divided by the number of cubic feet of gas burned in the calori- 
meter. Since a British thermal unit is equal to 778 foot pounds 
in mechanical energy, its mechanical equivalent is equal to the 
number of British thermal units multiplied by 77S. 

Another difference between the actual and theoretical results 
obtained is that due the perfect combustion in the calorimeter 
and the imperfect combustion in the engine. Since some gases 
require more air for their combustion than others, less of the 
first gas will be taken into the cylinder on a charge than the 
latter, which tends still further to balance the heating effect 
of rich and lean gases in the cylinder. 

(9) Gasifying Coal. 

Coal Gas or Illuminating Gas is generated by baking the coal 
in a closed retort or chamber out of contact with the air so 
that no combustion takes place either complete or incomplete. 
The hydrocarbon gases and tars are set free from the coal as 
permanent gases and are then piped to a gas holder after going 
through various purifying processes to remove the tars, oils, 
moisture and dust. The free or solid part of the coal remains 
in the retort in the form of coke, which is again burned for 
fuel. 

Because of its high carbon content, coal gas burns with a 
yellowish-white flame and is extensively used for lighting pur- 
poses, hence the name illuminating gas. In many ways coal 
gas is an ideal fuel for power purposes as it has a high calorific 
value (650-750 B.T.U. per cubic ft.), is supplied by the illumi- 
nating company at practically a constant pressure, and is uni- 
form in quality. Its only drawback is its comparatively high 
cost. 

This gas is always obtained from the city service mains as its 
preparation is too expensive and complicated for the gas en- 
gine owner. Because of its cost, the use of coal gas is restricted 
to small engines. 

(10) Water Gas. 

Water gas is made by blowing air through a thick bed of 
some coal that is low in hydrocarbons until the coal becomes 
incandescent, the gases that are formed are allowed to escape 
to the atmosphere. At this point a jet of steam is blown into 
the incandescent bed, which is broken up into its elements, oxy- 
gen and hydrogen, by the heat of the fuel. As there is no 



GAS, OIL AND STEAM ENGINES 33 

air present the oxygen combines with the carbon of the fuel 
to form carbon monoxide while the hydrogen goes free. Both 
of these gases, carbon monoxide and hydrogen, are collected 
and supplied to the engine. The production of water gas is 
intermittent, as the steam blast cools down the fuel bed, and 
requires further blowing before more steam can be passed. 
While this gas has a lower heating value than coal gas, it is 
much cheaper to make and all of the coal is consumed in the 
process. 

Water gas is high in hydrogen and is too "snappy" for gas 
engines; the hydrogen places a limit on the allowable com- 
pression. 

For each thousand feet of water gas generated, approximately 
24 pounds of water are required. 

By the introduction of hydrocarbons or vaporized oil, illumi- 
nating value is given to water gas, this process is called car- 
buretion. Carbureted gas is not usually used for power, as it 
is expensive, and is not proportionately high in heating value. 

(11) Blast Furnace Gas. 

Many steel companies are utilizing the unconsumed gas of 
the blast furnaces for power. 

Blast furnace gas is of very low calorific value, rarely if 
ever, exceeding 85 B.T.U. per cubic foot. This allows of very 
high compression, which greatly increases the actual power 
delivered by the engine. 

A smelter produces approximately 88,000 cubic feet of gas 
per ton of iron smelted. 

Blast furnace gas is so lean that it cannot be burned satis- 
factorily under a boiler; the high compression of the gas en- 
gine makes its use possible. 

(12) Producer Gas. 

Producer gas which is generated by the incomplete combus- 
tion of fuels in a deep bed is the most commonly used gas for 
engines having a capacity of 50 horsepower and over, because 
of the simplicity and economy of its production. While pro- 
ducer gas has been obtained from practically every solid fuel, 
of which coal, coke, wood, lignite, peat, and charcoal are ex- 
amples, the fuel most generally used is either coal or coke. 
While producer gas is much lower in calorific value than either 
natural or illuminating gas it gives admirable results in the gas 
engine and is a much cheaper fuel than coal gas in units above 



34 GAS, OIL AND STEAM ENGINES 

50 horse-power capacity. The fuel is completely burned to 
ash in the producer without the intermediate coke product that 
exists in the manufacture of coke. 

A producer consists of three independent elements as shown 
by Fig. F-6; the PRODUCER or generator (A), the steam boiler 
(B), and the SCRUBBER or purifier (C). The incandescent fuel 
(F) in the form of a cone lies on the grate bars (G) at the 
lower end of the producer. Above the burning fuel is a deep 
bed of coal (D) which reaches to the top of the producer at 
which point it is admitted to the bed through the charging 
valve or gate (H). The gas resulting from the combustion 
in the producer is drawn out of the tank through the gas out- 
let pipe (E) by the suction of the engine. The air for the 
combustion is drawn up through an opening in the ash pit 
(J) by the engine. 

When the oxygen of the air strikes the incandescent fuel 
on the grate it combines with a portion of it forming carbon 
dioxide (C0 2 ) which is an incombustible gas, but on passing 
through the burning fuel above this point, one atom of the 
oxygen in the C0 2 recombines with the fuel forming the com- 
bustible gas — carbon monoxide (CO). Because of the dis- 
tilling effect of the heat in the bed, the volatile hydrocarbons 
of the coal are set free and mingle with the CO formed by 
the combustion. The producer gas consists, therefore, prin- 
cipally of CO, with a certain proportion of the volatile hydro- 
carbons of the coal such as marsh gas, ethylene, and some oil 



^e tfr€ 



le hydrocarbons are easily condensed on coming into 
contact x - 

MtrTthe coal walls of the piping, to form trouble mak- 

ijior tJ-Lt"^ ot ^^ 

. to . xt oils, they must either be washed out of the gas 

pun er %r p asse( j a g a j n through the high temperature 
zone to convert th^ ln%p permanent gases. In the usual pro- 
ducer, the hydrocarbon, ^ reheated , as they form a consider- 
able percentage of the heat\ 4ue of the gas . After the volatile 
constituents are reheated, the\ ases pass through the boiler 
(B) which absorbs the heat of tv, e gas in generating steam, 
and from this point the gases enter £w rub ber where the dust 
and the residual tars are removed, TH - ^rubber, which is a 
sort^ of filter, is an important factor in the generating plant, 
for if the dust and dirt were allowed to pass into the cylinder 
of the engine it would only be a question of a showtime until 
the valves and cylinder would be ground to pieces. 

When the steam from the boiler is allowed to flow into the 



GAS, OIL AND STEAM ENGINES 



35 



ash pit of the producer and up through the incandescent fuel, 
the heat separates the water vapor into its two elements, oxy- 
gen and hydrogen. The oxygen set free combines with the 
carbon in the coal forming more carbon monoxide, while the 
hydrogen which is unaffected by the combustion adds to the 
heat value of the gas. The last additions to the combustion 
dut to the disassociation of the steam are really what is known 
as "water gas." A limited amount of steam may be admitted 




8AWDUST , 



ffig8ggg&&g|£3&gg 



DRY PURIFIER 




Fig. F-6. Diagram of Suction Gas Producer Showing the Generator, 
Boiler and Washer. 

continuously in this manner without lowering the temperature 
of the fuel below the gasifying point, and its presence is bene- 
ficial for it not only provides more CO and hydrogen but pro- 
duces it without introducing atmospheric nitrogen. The steam 
is also a great aid in preventing the formation of clinkers on 
the grate bars. Since the air used in burning the fuel in the 
first reaction contains about 79 per cent of nitrogen, which is 
an inert gas, the producer gas is greatly diluted by this unavoid- 
able admixture, which accounts for its low calorific value. 

While the air required for the combustion of the fuel is 
drawn through the producer by the suction of the engine in 
the example shown (SUCTION PRODUCER), there is a tvoe 



36 GAS, OIL AND STEAM ENGINES 

in common use called a PRESSURE PRODUCER in which the 
air is supplied under pressure to the ash pit by a small blower, 
which causes a continuous flow of gas above atmospheric 
pressure. 

Gas producers are divided into two classes: suction producers 
and pressure producers. The suction producer presents the 
following advantages: 

1. The pipe line is always less than atmospheric pressure, 
hence no leaks of gas to the air are possible. 

2. The regulation of the gas supply is automatic. 

3. No gas storage tank is required. 

4. The production of gas begins and stops with the engine. 

5. Uniform quality of gas. 

The suction producer is limited to power application and 
cannot be used where the gas is to be used for heating, as 
in furnaces, ovens, etc., or where the engine is at a distance 
from the producer, unless pumped to its destination. 

The pressure producer does not yield a uniform quality of 
gas, hence requires a storage tank where low quality gas will 
blend with gas of higher calorific values and produce a gas of 
fairly uniform quality. 

The pressure producer is adapted to the use of all grades of 
fuels, such as bituminous coal and lignite. 

Anthracite coal contains little volatile matter and is an ideal 
fuel for the manufacture of producer gas, while bituminous coal 
with its high percentage of volatile matter and tar, requires 
more efficient scrubbing, as these substances must be removed 
from the gas. 

On starting the producer shown by Fig. 6, the producer is 
filled with the proper amount of kindling and coal, and a 
blast of air is sent into the ash pit by a small blower, the 
products of combustion being sent through the by-pass stack 
(K) until the escaping gas becomes of the quality required for 
the operation of the engine. The by-pass valve is now closed, 
and the gas is forced through the scrubber to the engine until 
the entire system is filled with gas. When good gas appears 
at the engine test cock the engine is started, and the blower 
stopped, the gas now being circulated by the engine piston. 
The volume of gas generated by the producer is always equal 
to that required by the engine so that no gas receiver or 
reservoir is required. Because of the friction of the gas in 
passing through the fuel, scrubber and piping its pressure at 
the engine is always considerably below that of the atmosphere, 



GAS, OIL AND STEAM ENGINES 37 

which of course reduces the amount of charge taken into the 
cylinder. Because of the weak gas and the low pressure in 
the piping, it is necessary to carry a much higher compression 
with producer gas than with natural or illuminating gas. 

The efficiency of a producer is from 75 to 85 per cent, that 
is, the producer will furnish gas that has a calorific value of 
an average of 80 per cent of the calorific value of the fuel from 
which it is made, the remaining 15 to 20 per cent being con- 
sumed in performing the combustion. This is far above the 
efficiency of the furnace in a steam boiler, as an almost theo- 
retically exact amount of air can be supplied in the producer 
to effect the combustion, while in the boiler furnace about ten 
times the theoretical amount is passed through the fuel bed 
to burn it. Heating up this enormous volume of air to the 
temperature of the products of combustion consumes a large 
amount of # fuel and reduces the efficiency of the furnace con- 
siderably. Because of the reduction in the air supply, a gas 
fired furnace is always more efficient than one fired w T ith coal. 
Producer gas with 300,000 British thermal units per thousand 
cubic feet, and oil having 130,000 British thermal units per gal- 
lon will result in 1,000 cubic feet of gas being equal to about 
2.30 gallons of fuel oil. 

If the gas is to be used for heating ovens or furnaces in con- 
nection with the generation of power, the character of the fuel 
will be determined to a great extent by the requirements of the 
ovens and by the type of producer used, as each fuel will give 
the gas certain properties. Thus gas used for firing crockery 
will not be suitable for use in open hearth steel furnaces, as the 
impurities in the various fuels may have an injurious effect on 
the manufactured product. The cost of the fuel, cost of trans- 
portation, heat value, purity, and ease of handling are all 
factors in the selection of a fuel. 

The size and condition of a fuel is also of importance. Ex- 
ceedingly large lumps and fine dust are both objectionable. 

Wet fuel reduces the efficiency of the producer, as the water 
must be evaporated, this causing a serious heat loss. 

With careful attention a producer gas engine will develop 
a horse-power hour on from 1 to 1*4 pounds of anthracite pea 
coal, and in many instances the consumption has been less 
than this figure. The efficiency in dropping from full load to 
half load varies by little, one test showing a consumption of 
1.1 pounds of coal per horse-power hour at full load and 1.6 
pounds of coal at half load. Producer gas power is nearly as 



38 GAS, OIL AND STEAM ENGINES 

cheap as water power, in fact the producer gas engine has dis- 
placed at least two water plants to the writer's knowledge. 
According to an estimate made by a well known authority, 
Mr. Bingham, it is possible for a producer gas engine to gen- 
erate power for only .1 of one cent more per K.W. hour than 
it is generated at Niagara Falls. 

According to the United States Bureau of Mines, 

"The tests in the gas producer have shown that many fuels 
of so low grade as to be practically valueless for steaming pur- 
poses, such as slack coal, bone coal and lignite, may be econom- 
ically converted into producer gas and may thus generate suffi- 
cient power to render them of high commercial value. 

"It is estimated that on an average each coal tested in the 
producer-gas plant developed two and one-half times the 
power that it would develop in the ordinary steam-boiler plant. 

"It was found that the low-grade lignite of North Dakota 
developed as much power when converted into producer gas 
as did the best West Virginia bituminous coals burned under 
the steam boiler. 

"Investigations into the waste of coal in mining have shown 
that it probably aggregates 250,000,000 to 300,000,000 tons yearly, 
of which at least one-half might be saved. It has been dem- 
onstrated that the low-grade coals, high in sulphur and ash, 
now left underground, can be used economically in the gas pro- 
ducer for the ultimate production of power, heat and light, 
and should, therefore, be mined at the same time as the high- 
grade coal. 

"As a smoke preventer, the gas producer is one of the most 
efficient devices on the market, and furthermore, it reduces 
the fuel consumption not 10 to 15 per cent, as claimed for the 
ordinary smoke preventing device offered for use in steam 
plants, but 50 to 60 per cent. 

(13) Producer Gas From Peat. 

The production of gas from peat having a low water content 
(up to .about 20 per cent) for use in suction gas engines has 
already met with considerable success in Germany, but for a 
number of years efforts have been made to utilize peat with a 
water content as high as 50 to 60 per cent and thus eliminate 
the costly process of drying the raw material. 

Difficulties have been encountered in preventing a loss of 
heat through radiation and other causes, and in getting rid 
of the dust and tar vapors carried over by the gases to the 



GAS, OIL AND STEAM ENGINES 



39 



engine; but great strides bave been made recently in over- 
coming these obstacles. Peat with a water content up to 60 
per cent has been found to be a suitable fuel. Owing to its 
treat porosity and low specific gravity it presents a large com- 
bustion surface in the generator, so that the oxygen in the 
air used as a draft can easily unite with the carbon of the 
peat. 

One of the great difficulties is to eliminate the tar vapors 
that clog up many of the working parts of the engine. The 
passing of the gas through the wet coke washers and dry saw- 




Fig. F-7. German Producer for Generating Producer Gas from Peat. 

dust cleansers does not appear to have thoroughly remedied 
the evil. Efforts were therefore made to remove the tar-form- 
ing particles of the gas in the generator itself or to render them 
harmless. That of the Aktien-Gesellschaft Gorlitzer Masch- 
inenbau Ansalt und Eissengiesserei of Gorlitz, was displayed at 
the exposition at Posen in 1911. The gas from the generating 
plant was employed in a gas suction engine of 300 horse-power 
used to drive a dynamo for developing the electric energy for the 
exposition. The fuel used was peat with a water content of about 
40 per cent. The efficiency and economy results obtained were 
very promising. 



40 GAS, OIL AND STEAM ENGINES 

The advantages claimed for the Gorlitz engine are that the 
sulphurous gases and those containing great quantities of tar 
products are drawn down by the suction of the engine through 
burning masses of peat and thus rid of their deleterious con- 
stituents. The air for the combustion purposes is well heated 
before entering the combustion chamber, thereby producing 
economical results. It is claimed also that the gas produced 
by its system is so free from impurities that the cleaning and 
drying apparatus may be of the simplest kind. 

In Stahl und Eisen, an abstract is given of a paper by Carl 
Heinz describing a peat gas producer, built by the Goerlitzer 
Maschinenbauanstalt. We are indebted to Metallurgical and 
Chemical Engineering for the translation of this paper: 

Air and fuel enter the producer at the top, and the gas exit 
is in the center of the bottom so that the air is forced to pass 
through the center of the producer, decomposing the volatile 
matter into gases of calorific value. The moisture which is 
present in the peat fuel in considerable quantities must be 
taken into consideration. For its decomposition which passing 
through the hot-fire zone only a certain amount of heat is 
available. It is, therefore, important that the heat from the 
gasification be fully utilized. 

There are two kinds of heat losses in a gas producer, due 
to radiation and to the sensible heat of escaping gases. Both 
these amounts of heat, however, are utilized according to the 
special design of this producer. The air circulates first through 
the lower conduit and comes so in contact with the warm 
scrubber water. A part of the air which has been preheated 
is carried upwards through the pipe A in the center of the 
producer where it is thoroughly preheated by the hot gases 
and enters then the air superheater B in which the temperature 
rises to a still higher degree. 

The other part of the air passes through the feet of the 
producer into an air jacket which envelops the whole shell of 
the producer and enters finally the producer by the reversing 
valve C on top of the producer. In this way the outer surface 
of the producer is maintained at a temperature hardly higher 
than that of the surrounding air. The escaping gases are cooled 
down so far that the gas outlet into the scrubber may be 
touched by hand. All ordinary heat losses are thus made use 
of in the gasification process. 

If there is a large excess of moisture in peat? the process is 
somewhat modified by regulating both air supplies in such a 



(J AS, OIL AND STEAM ENGINES 41 

way that the gasification in the upper part of the fuel-bed 
takes place in two directions, one downwards and the other 
upwards. 

It seems that a content of 80 per cent moisture and 20 per 
cent dry fuel in the peat is about the limit permitting evapora- 
tion of the water, but it is, of course, impossible to obtain in 
this case a gas of calorific value. 

The modification of the process for very wet fuel is as 
follows: 

When the fire on top of the fuel bed appears to disappear, 
the heater opens the stack and valve D. Valve C is then closed, 
to prevent air from entering on top. The preheated air en- 
ters by D causing a down draft combustion due to the suction 
of the gas engine and an upward combustion due to the draft 
in the stack. The moisture is evaporated and escapes through 
the stack. When the fire has burned through at the top, the 
valve is switched over. The bad smelling gases^ rising from 
the scrubber enter the producer together with air and are there 
consumed. 

In commercial use at the exhibition in Posen the whole plant 
worked continuously day and night and cleaning of the gas en- 
gines was necessary only every three months. Slagging of 
ashes is done during the operation of the producer, without any 
nuisance from dust. 

The highest percentage of moisture in peat gasified was 50 
per cent. The fuel consumption per horse-power hour is 2.2 lb. 
(1 kg.) of peat. Careful tests made by Prof. Baer, of Breslau, 
showed that with a cost of peat of $1 per ton the kw-hour at 
the switchboard costs 0.15 cent. 

(14) Crude Oil Producers. 

The development of the crude oil gas producer, for which 
there is great demand, in oil regions remote from the coal 
field, has been exceedingly slow but it is believed that definite 
progress has recently been made along this line. The most 
recent notes on this subject relate to the Grine oil producer. 
In this type steam spray is used for atomizing the oil which is 
introduced into the upper part of the generator where partial 
combustion takes place. The downdraft principle is then ap- 
plied and the hydrocarbon broken up and the tar fixed by 
passing through a bed of incandescent coke. Mr. Grine reports 
that a power plant using one of these producers has been in 
operation a year in California. With crude oil as a fuel costing 



42 GAS, OIL AND STEAM ENGINES 

95 cents per barrel, or 2.3 cents per gallon, the plant is reported 
to develop the same amount of power per gallon of crude as is 
ordinarily developed by the standard internal combustion en- 
gine operating on distillates at 7 cents per gallon. Including 
the cost of fuel, labor, supplies, interest, depreciation and 
taxes, Mr. Grine states the cost per b.h.p. hour to be 0.76 cents 
for a plant of 100 h.p. rating. 

(15) Operation of Producers. 

A good producer operator is simply a good fireman, he must 
know how to keep a uniform bed of coal and how to draw the 
fire. While there are many thousands of men running pro- 
ducer plants without previous mechanical training, there are 
now but few steam engineers running steam engines of the same 
capacity but what have had at least two years' training and suffi- 
cient mechanical knowledge to pass an examination and obtain a 
license. While a considerable amount of skill is necessary 
to obtain the best efficiency from a producer, it is a knack that 
is easily acquired in a short time by "sticking around" the 
plant. Skill in operating a producer consists chiefly in keeping 
the right sort of a fire without damage to the lining by poking 
down ashes and clinkers. When a new plant is installed, the 
manufacturer generally sends an instructor to operate the plant 
for a short time so that with a few days running in his hands 
any man with ordinary intelligence can overcome the difficulties 
which arise from time to time. 

While there are many types of producers, the main difference 
will be found in the character of the draft, that is whether it 
is up, down, or crossways. Down draft producers are generally 
used with bituminous coals, as the tars and oils that emanate 
from the coal are drawn through the fire which converts them 
into a permanent gas, and avoids the difficulty of removing 
great quantities of the tar from the producer. An up draft 
producer will not do this as the gas is drawn directly into 
the mains without coming into contact with the fire. This 
would result in considerable expense due to the frequent 
cleaning. Anthracite coal which does not contain much tar 
can be used successfully in an up draft producer. 

A compromise between the up draft and down draft producer 
is had in the DOUBLE ZONE producer, which "burns the 
candle at both ends" as it were, a fire being at both the top and 
bottom of the producer. Nearly any class of fuel may be 
used with this type. 



GAS, OIL AND STEAM ENGINES 43 

It should be remembered that a hot fire and fuel are required 
for the manufacture of gas, and that the ash pit and grate must 
be kept clear of the ashes and clinkers that not only reduce 
the temperature of the fire, but also reduce the gas available at 
the cylinder by increasing the friction. Shaking down and 
cleaning out will in nearly every instance start a bucking pro- 
ducer into operation. 

When operating under furl load a much hotter fire is re- 
quired than when operating under a reduced load, or the pro- 
ducer will not furnish the necessary gas. According to the 
size of the producer, the depth of the incandescent fuel will 
run from 30 inches in the large sizes to 15 inches in the 
smaller. After being charged up, suction producers will con- 
tinue to give gas in sufficient quantities with the bed at half 
this depth. This is only possible with a hot producer, and 
when no fuel is being fed, as the feeding of a cold charge will 
reduce the output. A steady depth of fire should be kept to 
maintain a uniform quality of gas. 

In suction producers careful watch should be kept for leaks, 
as the gas being below atmospheric pressure gives no outward 
signs of dilution. If water seals are used in the system they 
should be given careful attention. When using coals that are 
rich in tar or hydrocarbons, or with fuels that have much 
fine dust, considerable trouble is had with some types of pro- 
ducers due to "caking" or to the adhesion of the coal particles 
to the walls of the producers or to their adhesion to one another. 
In the latter case the "stickiness" of the fuel prevent the 
proper feed. This difficulty may often be overcome by a 
change in the rate of feeding or by regulating the depth of 
the incandescent bed. 

Porosity of the fuel, and the rate at which the air is sup- 
plied to the producer determines the depth of the incandescent 
bed. Particular care should be taken that the blast or draft 
occurs evenly over the fire surface, and that no holes occur 
in the fire which will cause more rapid combustion in one 
spot than in another. Neglect of this precaution not only 
causes a waste of fuel but often results in the fuel "arching" 
and preventing further feed. The producer should be so pro- 
portioned that at full load, the rate of combustion does not 
exceed 24 pounds of fuel per square foot of producer area 
per hour. 

In his researches, Professor Bone (Iron and Steel Institute, 
May, 1907) has shown that up to 0.32 lbs. of steam per lb. of 



44 GAS, OIL AND STEAM ENGINES 

coal can be completely decomposed in a producer, but that, 
from 0.45 lbs. to 0.55 lbs. should be used, approximately 80% 
more. 

Now, in considering the question of the proper proportion 
of steam for the production of gas for power purposes we must 
bear in mind that as much heat as possible should be utilized 
in the producer itself. Some manufacturers of plant go so 
far as to state that as much as 1 lb. of steam per lb. of coal 
should be used, but we are safe in saying that 0.5 lb. to 0.7 lb. 
should be the figure for a power plant. The common practice 
is to use a blast saturation of 55% whenever the clinkering char- 
acter of the coal renders it possible. This figure corresponds 
to about .57 of steam per lb. of coal gasified. 

It is of the utmost importance that the proportion of steam 
and air should be constant, and the best figure being de- 
termined, it should not be varied to any degree. It is equally 
important that the fuel depth should be left constant. By this 
I mean that not only should the coal in the producer be kept 
at a specific level, but the position of the fire on the ash bed 
should be kept as near as possible a fixed point. Ashes should 
be drawn at regular intervals, or, if desired, continuously by 
mechanical means. 

Further, the supply of air and steam should be regularly 
distributed, so that the velocity of the gases through the fuel 
shall be as nearly as possible regular across its whole area. 

In some cases the by-products of a producer, such as am- 
monia, tar, etc., have a commercial value, and if a large amount 
of gas is generated it will sometimes pay to select a fuel that is 
rich in these particular substances. 

(16) Coal 

Coal which is the basis of producer gas, is composed gen- 
erally speaking of the combustible matter, moisture, ash and 
sulphur. The combustible element may be subdivided into the 
HYDROCARBONS, OR VOLATILES, and the solid fixed car- 
bon. The exact composition of coal is generally given by what 
is known as PROXIMATE analysis, which analysis divides the 
constituents of the coal into five groups, viz.: MOISTURE, 
VOLATILES, FIXED CARBON, ASH, and SULPHUR. 
Ultimate analysis resolves the coal into its ultimate chemical 
elements, such as hydrogen, carbon, nitrogen, sulphur, etc., and 
being a difficult and tedious process it is not much used. 



GAS, OIL AND STEAM ENGINES 



45 



The proximate analysis gives all the necessary information 
and takes less time to perform. 

The CALORIFIC VALUE of a fuel may be calculated from 
its analysis, or may be determined by means of the CALORI- 

VALUES OF COAL 



Location 
of 


PROXIMATE ANALYSIS 


Calorific 
Value in 
B. T. U. 


Mine 


Moisture 


Volatile 
Matter 


Fixed 
Carbon 


Ash 


Sulphur 


per Lb. 
of Coal 


ANTHRACITE 

Northern Pa. 


3-39 


4.41 


83-30 


8.i 7 


•73 


13,200 


Eastern Pa. 


• 3 70 


307 


86.42 


6.18 


.63 


i3»44o 


Western Pa. 


3.12 


376 


81.60 


10.61 


•53 


12,875 


SEMI- 
ANTHRACITE 


1.25 


8.15 


83-30 


6 27 


1.63 


13,900 


SEMI- 
BITUMINOUS 

Pennsylvania 


.80 


15.60 


77.40 


5-35 


.85 


14,900 


Pennsylvania 


i-55 


16.45 


7 J -5o 


8.63 


1.87 


14,200 


Pocahontas 
Va. 


1. 00 


21.00 


24.40 


3.02 


.58 


15.100 


West 
Virginia 


.90 


17-83 


77.70 


3-3o 


.27 


15.230 


BITUMINOUS 

Youghiogheny 
Pa. 


1. 00 


36-50 


59.00 


2-59 


.86 


14.400 


Sample No. 2 " 


1.20 


30.18 


5900 


8.84 


•78 


14,000 


Hocking 

Valley 


6.5 


35-o6 


48.80 


8.05 


i.59 


12.100 


Kentucky 


4.00 


34.00 


54-7o 


7.00 


•03 


12,800 


Indiana 


8.00 


30.20 


54 20 


7.60 




12,500 


Illinois 


10.50 


36 15 


37.00 


12.90 


3-45 


10,500 


Colorado 


6.00 


38.01 


47.90 


8.09 




12,200 


LIGNITE 


9.00 


42 26 


44 30 


327 


1. 18 


11,000 



46 GAS, OIL AND STEAM ENGINES 

METER from a sample of the coal; the latter method is the 
most reliable. Table gives approximately the calorific values, 
and the proximate analysis of several representative coals from 
various sections of the country. The values given in the table 
are not exact, as the coal from each locality varies considerably 
in quality, but the figures will indicate what may be expected 
from each type of coal. 

Connellsville, Pa., Coke has a calorific value of approximately 
13,000 B.T.U.S. per pound, contains no volatile matter, and has 
an approximate content of 10% ash. Coke is a valuable fuel 
for the gas producer, but is rather expensive. It is clean and 
the absence of volatile matter reduces the "scrubbing" problem 
to a minimum. 

Small coal such as buckwheat and pea contain a much higher 
percentage of moisture than given in the table, running from 
5% to 10% higher than the given values. 

Bituminous coal is high in hydrocarbons or volatiles which 
condense easily and form tar. If the tar is not removed or 
converted into a permanent gas, it will clog the passages of the 
producer and the engine and cause trouble. 

The removal of the tar and ash from a gas is called SCRUB- 
BING, and is performed by a device much resembling a filter. 
Anthracite coal and coke are low in volatiles or hydrocarbons, 
and therefore do not cause trouble with tar deposits. 

A high percentage of volatile matter also causes trouble by 
the tar cementing the particles of fuel together. This inter- 
feres with the proper action of the producer. 

Fuels having a high percentage of ash call for perfect filter- 
ing or "scrubbing" as such fuels will fill the gas passages with 
dust. Dust should be kept out of the engine at all costs, for 
the dust even in a quantity will cause wear in the cylinder. 

Depending on the quality of the fuel, bituminous coal will 
produce about Ay 2 pounds of ammonia and 12 gallons of tar 
with about 5% of sulphur. 

Anthracite coal will produce approximately six pounds of 
tar, and two pounds of ammonia with traces of sulphur. 

Loose Anthracite coal requires approximately 40 cubic feet 
of storage space per ton of 2240 pounds and weighs about 56 
pounds per cubic foot (market sizes). 

Loose Bituminous coal requires approximately 45 cubic feet 
of storage space per ton of 2240 pounds, and weighs about 52 
pounds per cubic foot in market sizes. 

Dry coke requires approximately 85 cubic feet of storage 



GAS, OIL AND STEAM ENGINES 47 

space per ton of 2240 pounds, and weighs about 26 pounds per 
cubic foot. 

(17) Fuel Oils. 

Crude oil, a natural product, is the base of the fuels most 
commonly used in internal combustion engines, especially in 
the smaller sizes. From this compound the following deriva- 
tives are obtained by the process of distillation, a separation 
possible because of the different boiling points of the various 
oils. As each derivative or DISTILLATE has a different boiling 
point, the temperature of the crude oil is maintained at the 
boiling point of that product that is desired, and the resulting 
vapor is condensed. The following list is not anywhere near 
complete for there are several hundred distinctly different dis- 
tillates, but it contains those that are of the most interest to 
the engine man. 

1. Crude Oil. 

2. Gasoline. 

3. Naptha. 

4. Solar Oif. 

5. Kerosene. 

The specific gravity of the crude oil as obtained in the field 
will range from 12° to 56° Beaume scale. The crude from 
Pennsylvania will average 40° Beaume while that from Texas 
will average 20°. The accompanying table will give the calo- 
rific values and general properties of the principle liquid fuels. 
It should be noted that the weight or density of the liquids is 
given in terms of specific gravity or Beaume scale, in which the 
SPECIFIC GRAVITY of the fuel is the ratio of its weight per 
unit volume to the weight of an equivalent volume of water. The 
specific gravity of a liquid is generally determined by an in- 
strument known as a HYDROMETER which consists of a glass 
tube sealed at both ends carrying a graduated scale on the 
upper portion of the stem, and a ballast weight of shot or 
mercury at the bottom. 

The hydrometer is floated in the liquid to be tested, and the 
lower the specific gravity, the lower the hydrometer sinks, 
and vice versa. The specific gravity of the liquid is read 
directly from the graduation on the stem that are on a level 
with the surface of the liquid under test. As in the case of 
thermometers, hydrometers are all graduated in two different 
scales, the specific gravity scale and the Beaume scale. The spe- 



48 



GAS, OIL AND STEAM ENGINES 



cine gravity scale reads at 1.00 when floated on distilled water, 
and the Beaume at 10.00 when floated on the same liquid. 

A difference in temperature affects the density of a liquid, 
hence all* hydrometers are graduated for a standard temperature 
of 60°F unless otherwise specified. For a difference of 10°F 
there is a variation of one degree gravity in the Beaume scale, 
and for a difference of 20°F in temperature there is a change 
of one degree on the specific gravity scale. If the temperature 
differs from 60°F, the corresponding correction should be made 
in the reading. 

To convert the Beaume reading (B) to terms of the specific 
gravity scale (S) use th^fc- following formula: 
140 
S = = specific gravity. 



130 + B 
140 
B = = 



Beaume scale. 



Properties of Oils 

Degrees Specific Weight B. T. U.'S B. T. U.'S 
Baume Gravity per gal. per lb. per gal. 

Gasoline 67.2 .7125 5.932 21120 125,284 

Heavy naphtha 64.6 .7216 6.011 20527 123,388 

Kerosene 48.8 .7848 6.538 20018 130,877 

W. Virginia crude 40.0 .8251 6.874 19766 135,871 

Penn. fuel oil 31.9 .8660 7.215 19656 141,818 

Kansas crude 29.0 .8816 7.345 19435 142,750 

Fuel oil 22.7 .9176 7.645 19103 146,042 

California crude 22.5 .9248 7.710 18779 144,786 

California crude 15.2 .9646 8.036 18589 149,381 

Alcohol, 95% 41.9 .816 6.798 10500 71,380 

It will be noted that the petroleum products contain an enor- 
mous amount of heat energy, nearly 25% more than that of the 
same weight of pure carbon. It will also be noted that the 
lighter products such as gasoline, kerosene, etc., have more heat 
per pound but less per gallon than the heavier oils. This is rather 
confusing at first, but as will be seen after deliberation that 
the heavier fuel is the most economical since the least is used 
per horse-power, and is bought by the gallon. The calorific 
values given in the table are obtained by a colorimeter, and are 
burnt in the open air, and consequently have a different heating 
value when under compression in the cylinder of the engine. 



GAS, OIL AND STEAM ENGINES 49 

In all cases the liquids are vaporized before being introduced 
in the cylinder, the more volatile liquids such as gasoline being 
Converted into vapor at atmospheric temperature, and the 
heavier non-volatiles by being sprayed into a heated vessel or 
preheated air. The percentage of liquid fuel contained in a cubic 
foot of air vapor mixture depends on the temperature, the boil- 
ing point of the liquid and upon the pressure and humidity. 

Gasoline consists principally of compounds of the methane 
series, the one representative of gasoline being Hexane (C 6 H U ). 
It requires 15.5 pounds of air for combustion theoretically and 
about 10 per cent more in practice. The formation of gasoline 
vapor produces a drop in temperature of 50°F, and should be 
heated 100°F above the atmosphere for the best results. The 
volume of air required for the combustion is about 192 cubic 
feet. With alcohol at 20 cents per gallon and gasoline at \2 l / 2 
cents the number of B.T.U.'s for one cent in the case of alcohol 
is 3594 and 9265 in the case of gasoline. In the engine the 
difference is not so great owing to the difference in compression 
pressures. 

(18) Tar for Fuel. 

Because of the increasing interest in the Diesel type engine 
and the low grade fuels that it has made possible, we quote 
the specifications laid down by Dr. Rudolph Diesel, the in- 
ventor, before the English Institution of Engineers. 

(1.) Tar-oils should not contain more than a trace of consti- 
tuents insoluble in xylol. The test on this is performed as 
follows: — 25 grammes (0.88 oz. av.) of oil are mixed with 25 
cm. 3 (1.525 cub. in.) of xylol, shaken and filtered. The filter- 
paper before being used is dried and weighed, and after filtra- 
tion has taken place it is thoroughly washed with hot xylol. 
After re-drying the weight should not be increased by more 
than 0.1 gr. 

(2.) The water contents should not exceed 1 per cent. The 
testing of the water contents is made by the well-known xylol 
method. 

(3.) The residue of the coke should not exceed 3 per cent. 

(4.) When performing the boiling analysis, at least 60 per 
cent by volume of the oil should be distilled on heating up to 
300° C. The boiling and analysis should be carried out accord- 
ing to the rules laid down by the Trust. (German Tar Produc- 
tion Trust on Essen-Ruhr.) 

(5.) The minimum calorific power must not be less than 



50 GAS, OIL AND STEAM ENGINES 

8,800 cal. per kg. For oils of less calorific power the purchaser 
has the right of deducting 2 per cent of the net price of the 
delivered oil, for each 100 cal. below this minimum. 

(6.) The flash-point, as determined in an open crucible by 
Von Holde's method for lubricating oils, must not be below 
65° C. 

(7.) The oil must be quite fluid at 15° C. The purchaser has 
not the right to reject oils on the ground that emulsions appear 
after five minutes' stirring when the oil is cooled to 8°. 

Purchasers should be urged to fit their oil-storing tanks and 
oil-pipes with warming arrangements to redissolve emulsions 
by the temperature falling below 15° C. 

(8.) If emulsions have been caused by the cooling of the 
oils in the tank during transport, the purchaser must redissolve 
them by means of this apparatus. 

Insoluble residues may be deducted from the weight of oil 
supplied. 

Coal tar oil is the distillate of the tar obtained from gas 
works, from which all valuable commercial materials such as 
aniline have been removed. Coal oil tar is also known as 
creosote oil and anthracene oil, the heat value of which is not 
quite 16,000 B.T.U. per pound. 

(19) Residual Oils. 

Residual oil is the residue left after the lighter oils have been 
distilled from the petroleum, which before the advent of the 
Diesel engine were useless. Residual oil which was hardly 
fluid at ordinary temperatures has been successfully used in the 
Diesel and semi-Diesel types of engines, by preheating it be- 
fore admission to the inlet valves. The enormously increased 
demand for gasoline has resulted in a great increase of the 
formerly useless residual oil so that it is possible that the de- 
mand for gasoline will make the production of the residual great 
enough so that it can be seriously considered as a fuel- 

(20) Gasoline. 

Gasoline is by the far the most widely used fuel for internal 
combustion engines because of its great volatility and the ease 
with which it forms inflammable mixtures with the air at ordi- 
nary temperatures. Another point in its favor is the fact that 
it burns with a minimum of sooty or tarry deposits, without 
a disagreeable smell with moderate compression pressures and 
without preheating through a' wide range of air ratios. Gasoline 



GAS, OIL AND STEAM ENGINES 51 

is a product of crude oil from which it is obtained by a process 
of distillation, and as it forms but a small percentage of the 
crude oil it is rapidly becoming more and more expensive as 
the demand increases. Some Pennsylvania etude oils will yield 
as much as 20 per cent of their weight in gasoline, while the low 
grade Texas and California crudes very seldom contain more 
than 3 per cent. 

When considered as a term applying to some specific product, 
the word "Gasoline" is a very flexible expression as it covers a 
wide range of specific gravities, boiling points, and composi- 
tions, the latter items depending on the demand for the fuel 
and the taste of the manufacturer. Since the specific gravity 
of gasoline is a factor that determines its suitability for the 
engine, at least in regard to its evaporating power or volatility, 
it is graded according to its density in Beaume degrees as de- 
termined by the hydrometer. According to this scale gasoline 
will range from 85° to 60°^ Beaume, and even lower, although 
60° is supposed to mark the lowest limit and to form the dividing 
line between gasoline and naphtha. 

The density of the gasoline in Beaume degrees is an index 
to the volatility, for the higher the degree as indicated on the 
hydrometer, the higher is the volatility at a given temperature, 
consequently a high degree gasoline will give a better mixture 
at a low temperature than one of a low degree. In cold weather 
all gasoline should be tested with a hydrometer when pur- 
chased to insure a grade that will be volatile enough for easy 
starting when the engine is cold. In cold weather the gasoline 
should not be lower than 68°, and for the best results should 
be above 72°, at least for starting the engine. Good gasoline 
should evaporate rapidly and should produce quite a degree of 
cold when a small amount is spread on the palm of the hand, 
and it should leave neither a greasy feeling nor a disagreeable 
odor after its evaporation. 

The high gravity gasoline is of course the most expensive, 
as there is less of it in a gallon of the crude oil from which it is 
made; gasoline of 76° Beaume being approximately 15c. per gal- 
lon in carload lots, while naphtha of 58° Beaume brings Sy 2 c. 
per gallon. 

The calorific value of gasoline increases as the gravity Beaume 
decreases per gallon; 85° gasoline having approximately 113,000 
B. T. U, per gallon while 58° naphtha has an approximate value 
of 122,000 B.T.U. per gallon. The calorific value remains nearly 
constant per pound for all gravities. 



52 GAS, OIL AND STEAM ENGINES 

It should be remembered that heat is absorbed in evaporating 
gasoline as well as in evaporating water, and that effects of 
cold weather are greatly increased by the amount of heat ab- 
sorbed, (or cold produced) by the vaporization of the fuel. 
While the heat absorbed by evaporating a given quantity of 
gasoline is only .45 per cent of that absorbed by an equal amount 
of water, it is a fact that this heat must be supplied from some 
source to prevent a reduction in the vapor density. In starting 
the engine, the heat of evaporation is supplied by the atmosphere* 
and should the temperature of the air be below that required 
for a given vapor density, the engine will refuse to start. 

By the use of two tanks and a three way valve, it is possible 
to use two grades of fuel: one tank containing high gravity 
gasoline, and the other low gravity; the high gravity being used 
for starting the engine in cold weather, and the cheaper, low 
gravity, being used for continuous running after the engine is 
warmed up — the change of fuels being made by throwing over 
the three way valve. 

The VAPOR DENSITY of gasoline vapor is the ratio of the 
weight of the vapor compared with the weight of an equal vol- 
ume of dry air at the same temperature. If the weight of a cubic 
foot of gasoline vapor is divided by the weight of a cubic foot of 
air the same temperature the result will be the vapor density of 
the gasoline vapor. Compared to air, the gasoline vapor is 
quite heavy so that if a small quantity of gasoline is poured 
on the top of a table, the vapor will flow over the edge of the 
table and drop to the floor where it will remain until it has 
united with the air by the process of diffusion. Experiments 
have shown that pure, dry gasoline vapor has a density of 
about 3.28, or in other words weighs 3.28 times as much as an 
equal volume of dry air. This weight of course is the weight of 
pure vapor which is considerably heavier than the mixture of 
vapor and air that is used in the cylinder of the engine. 

Dampness, or the presence of water vapor in the air reduces 
the quantity of gasoline vapor taken up by the air, but only by a 
small amount, the maximum difference being only about 2 per 
cent. Since it is very likely that the water vapor is broken up 
into its original elements, oxygen and hydrogen, by the heat of 
the combustion it is likely that there is no heat loss due to the 
vapor passing out through the exhaust. The principal trouble 
due to dampness is the mixture of water and liquid gasoline 
caused by the condensation of the water vapor. 

All gasolines and oils contain water to a more or less de- 



GAS, OIL AND STEAM ENGINES 53 

gree, hence provision should be made for the draining of the 
water which collects in the bottom of the tank. Water in liquid 
fuels is the cause of much trouble. 

Water in gasoline may be detected by dropping scrapings 
from an indelible pencil into a sample of the suspected fluid. If 
water is present in any quantity the gasoline will assume a 
violet color. 

In filling a supply tank with gasoline, a chamois filter or 
chamois lined funnel should always be used, as the chamois 
skin allows the gasoline to pass but retains the water and im- 
purities contained therein. There are many funnels of this type 
now on the market. 

The rate at which gasoline burns depends on the amount of 
surface presented to the air by the fluid, for a given quantity of 
gasoline burns faster in a wide shallow vessel than in a deep jar. 
Since a spray of minute particles presents an enormously greater 
surface than the liquid its burning speed is correspondingly 
greater, and as a true vapor has an almost limitless area, its 
speed is much greater than that of the spray, the combustion 
under the latter condition being almost instantaneous. Besides 
the question of subdivision of the liquid, the rate of combustion 
also depends on the intimacy of contact of the vapor with the 
air and on the pressure applied to the vapor as previously ex- 
plained under the head of "COMPRESSION" in another chapter. 
CARBURETING AIR, or producing an explosive mixture of 
gasoline vapor and air is accomplished by two different methods, 
first by passing the air over the surface of the liquid, or by pass- 
ing it through the liquid in bubbles; second by spraying the 
liquid into the air. The latter is the method most generally in use 
at the present time, the spray being formed by the suction of the 
intake air upon the open end of the spray nozzle. The vapor 
density of the mixture thus formed depends on the suction of 
the air and upon the nozzle opening, either of which may be 
varied in the modern carburetor to vary the richness of the 
mixture. 

As a suggestion to the users of gasoline we append the 
following remarks. 

Gasoline vapor will readily combine with air to form ex- 
plosive mixtures, at ordinary temperature. This property at 
once makes it the most suitable fuel and the most dangerous 
to handle. 

Never fill tanks or expose gasoline to the air in the presence 
of an open flame, or do not attempt to determine the amount 



54 GAS, OIL AND STEAM ENGINES 

of gasoline in a tank with the aid of a match. There are a 
number of people who have successfully accomplished this feat, 
and a very great number who have not. 

Be very sparing in the use of matches around a gasoline 
engine; there are such things as leaks. 

Always carefully replace the stopper or filler cap in a gaso- 
line tank after filling. Never use the same funnel for water 
and gasoline, and avoid any possibility of water finding its way 
into the tank. 

If you do succeed in igniting a quantity of free gasoline, do 
not attempt to extinguish the fire with water. Pouring water on 
burning gasoline spreads the fire. Extinguish it with earth or 
sand, or by the use of one of the dry powder extinguishers now 
on the market. 

Water may be removed from gasoline by placing a few lumps 
of dessicated calcium chloride in the tank, the amount depend- 
ing on the quantity of water. 

Calcium chloride, has a great capacity for absorbing water, 
and in a short space of time will absorb all of the moisture 
contained in the tank. 

The best way to introduce the chloride is to wrap the lumps 
in a sheet of wire gauze and lower into tank with a wire, the 
wire allowing it to be easily removed when saturated with water. 

(21) Benzol. 

Benzol has been used to some extent in Europe as a fuel, 
its use being due to the rapidly increasing cost of gasoline. 

Benzol is a distillate of coal tar, and is a by-product of the 
coke industry. In England benzol brings approximately the 
same price as gasoline (called petrol), but benzol proves eco- 
nomical for the reason that it develops more power per gallon. 

Benzol is not as volatile as gasoline, but is sufficiently volatile 
to allow of easy motor starting. 

Benzol is also used for denaturing alcohol. 

(22) Alcohol. 

Alcohol is of vegetable origin, being the result of the de- 
structive distillation of various kinds of starchy plants or vege- 
tables. Starch is the base of alcohol. 

As a fuel, alcohol has much in its favor, as it causes no carbon 
deposit, has smokeless and odorless exhaust, can stand high 
compression, and requires less cooling water than gasoline, as 



GAS, OIL AND STEAM ENGINES 55 

the heat loss is less through the cylinder walls, and for this 
reason it is more efficient fuel than gasoline. 

At the present time the price of alcohol prohibits its general 
use. In order that alcohol equal gasoline in price per horse 
power hour, it should sell for 10c. per gallon, the price of 
gasoline being 15c. per gallon. 

Alcohol can be used in any ordinary gasoline engine with 
readjustment of carburetor. and the compression. 

The nozzle in the carburetor has to be of larger bore for alco- 
hol than for gasoline, and the compression for alcohol than for 
in the neighborhood of 180 pounds per square inch. 

The inlet air should be heated to about 280°F for alcohol 
fuel; approximately 6% of the heat of the alcohol is required 
for its vaporization. Alcohol is much safer to handle than 
gasoline owing to its low volatility. 

90% alcohol has a calorific value of 10,100 B.T.U. per pound, 
its specific gravity being .815. 

WOOD, or METHYL alcohol is made by distilling the starch 
contained in the fibres of some species of wood (Poisonous). 

GRAIN, or ETHYL alcohol is the result of the distillation of 
the starch contained in grains, potatoes, molasses, etc. ETHYL, 
or GRAIN alcohol rendered unfit for drinking by the addition 
of certain substances, is called DENATURED ALCOHOL. 
The process of denaturing does not affect the calorific value of 
alcohol to any extent. 

(23) Kerosene Oil. 

Kerosene is a fractional distillate of crude oil which has a 
considerably higher vaporizing temperature than gasoline. It 
does not form an inflammable mixture with the air at ordinary 
temperatures, but is vaporized in practice by spraying it into a 
chamber heated to above 200°F. Kerosene forms a greater per- 
centage of crude oil than gasoline and as there has been less 
demand for it up to the present time it is much cheaper. Penn- 
sylvania crude oil produces only 20 per cent of gasoline while 
the kerosene contents will average nearly 42 per cent accord- 
ing to figures at hand. 

Kerosene has a very high calorific value per gallon, 8.5 gal- 
lons of" kerosene having the same heating effect as 10 gallons 
of gasoline. Because of its high calorific value and its low cost 
per gallon, many types of engines have been developed for its 
use during the last few years, several of which have been very 
successful. Before the advent of the modern kerosene engine 



56 GAS, OIL AND STEAM ENGINES 

much difficulty was experienced with the fuel because of its 
high vaporizing temperature and its tendency to carbonize in 
the cylinder, but as the price of gasoline continued to rise, the 
inventive genius of the gas engine builder overcame these 
troubles so that the kerosene engine is now as reliable as any 
form of prime mover. 




Kerosene Vaporizer on Fairbanks-Morse Engine. The Engine is Started 
on Gasoline and When Hot, the Kerosene Feed is Turned on. 

Any gasoline engine will run on kerosene, after a manner, if 
the engine is thoroughly heated to insure the vaporization of 
the kerosene, and if the fuel heated in the carburetor. Such an 
arrangement is make-shift, however, and is not productive of 
good results in continuous service. If kerosene is to be used 
as a regular fuel, a kerosene engine should be used to avoid 
vaporizing and carbonizing difficulties as well as the sooty, 
offensive exhaust, and the loss of fuel represented by the soot. 



GAS, OIL AND STEAM ENGINES 57 

Many kerosene engines are arranged to start on gasoline, 
and, after becoming heated, have the running feed of kerosene 
admitted through a three way valve. The gasoline feed is then 
stopped. 

The above arrangement admits of easy starting in all weathers 
and temperatures. 

In the Diesel engine there is no evaporating of fuel, and no 
deposits of carbon because of the high temperature of the com- 
bustion chamber. With engines that draw the mixture of vapor 
and air into the cylinder there are several methods of applying 
heat to the liquid, and the combustion of the vapor thus formed 
is perfected by the injection of water into the combustion 




Kerosene Vaporizer on Fairbanks-Morse Vertical Engine. Started on 
Kerosene Directly by Heating Vaporizer with Torch. 

chamber. It has been found by experiment that a small amount 
of water vapor introduced into the cylinder of a kerosene en- 
gine makes the engine run more smoothly and prevents a 
smoky exhaust and carbon deposits in the cylinder. The water 
is introduced into the cylinder through an atomizer in the form 
of a mist or fog, the particles of water being in a very finely 
subdivided state. 

The deposits of free carbon (soot) caused by the "cracking" 
or decomposition of the kerosene vapor before ignition, due to 
the high temperature of the cylinder, are burnt to carbon dioxide 
by the oxygen of the water which is also set free by the heat of 
the cylinder. This produces an odorless gas (C0 2 ) which in- 
dicates complete combustion. Besides the increase of fuel ef- 
ficiency due to the water vapor, the cylinder is more thoroughly 
cooled and is more efficiently lubricated because of the reduc- 
tion in temperature. 



CHAPTER III 
WORKING CYCLES 

(24) Requirements of the Engine. 

In order that an internal combustion engine shall operate 
and develop power continuously the following routine of events 
must occur in the cylinder in the following order, no matter 
what the type of engine. 

(1) The cylinder must be filled with a combustible mixture 
of air and gaseous fuel at as nearly atmospheric pressure as 
possible. 

(2) The mixture must be compressed in order to develop 
the value of the fuel. 

(3) Ignition must take place at the end of the compression 
stroke or at the highest point of compression. 

(4) Complete combustion of the fuel must follow the ignition 
of the charge, with an increase of temperature and pressure 
which will act on the piston to the end of the power stroke. 

(5) After the piston has completed the working stroke the 
products of combustion must be ejected from the cylinder com- 
pletely to make way for the admission of the new combustible 
mixture. 

With the exception of the Diesel engine which (1) fills the 
cylinder with pure air without the fuel, and (2) injects the fuel 
after compression, all internal combustion engines not only per- 
form each of these operations but proceed with events in the 
order given as well. The accomplishment of the five acts is 
called a "cycle of events,'' or a "CYCLE," and the series is per- 
formed in different ways in different types of engines. In the 
operation of the engine, the series of events occur over and over 
again, always in the same order, 1-2-3-4-5, 1-2-3-4-5, 1-2-2-3-4-5, 
etc. The five events are generally given in terms of the num- 
ber of strokes of the piston taken to accomplish the complete 
routine, thus a two stroke cycle engine performs the series in 
two strokes, and a four stroke cycle engine in four strokes, and 
so on. 

In order to obtain the benefits of high compression, perfect 

58 



GAS, OIL AND STEAM ENGINES 59 

scavenging of the products of combustion from the cylinder and 
perfect mixtures, a great variety of engines have been developed 
in which the number of strokes taken to accomplish the five 
events varies. In some engines the cycle is accomplished in 
two strokes, in other engines it is accomplished in six strokes, 
but in the great majority of cases the cycle is performed in 
either two or four strokes, and as these are by far the most 
common routines, we will confine our description to engines of 
these types. 

(25) Four Stroke Cycle Engine. 

The four stroke cycle engine, some times improperly called 
the "four cycle" engine is the most widely used type for all 
classes of service, except possibly for marine work. Its ex- 
tended use is due to its superior scavenging, high efficiency and 
reliability, although it is somewhat more complicated than the 
two stroke cycle type. Its ability to function properly under a 
wide variation of speed has driven the two stroke cycle type 
out of the automobile field, and its many admirable character- 
istics have cut a wide swath in the marine field, the stronghold 
of the two stroke cycle type. 

A four stroke cycle engine performs the cycle of events in 
four strokes or two revolutions, only one of the strokes being a 
power of working stroke. In a single cylinder engine the ex- 
plosion in the working strokes supplies enough power to the 
fly-wheel to carry the engine and its load through the remain- 
ing three strokes. Thus the energy stored in the fly wheel is 
sufficient to carry not only the load during the idle strokes but 
to "inhale" and compress the charge as well. Due to the long 
interval that exists between explosions, they are corresponding 
heavy and are productive of heavy strains in the engine and are 
the cause of considerable vibration. 

To reduce the ill effects of the heavy intermittent blows, the 
majority of automobile and stationary engines are provided 
with two or more cylinders, the power being equally divided 
among them. In a four cylinder engine, there are four times 
as many impulses as in a single cylinder engine and the blow 
dealt by the individual cylinder is only one-quarter as great. 
While a single cylinder engine has an impulse only once in 
every other revolution, the four cylinder has two impulses in 
one revolution. Besides the advantages gained by increasing 
the impulses, the mechanical balance of a multiple cylinder en- 
gine is always better than that of a single and is also much 



60 



GAS, OIL AND STEAM ENGINES 




Fig. 4. Diagrammatic View of Four Stroke Cycle Engine with the Piston 
in Various Positions Corresponding with the Five Events. Diagram 
A — Suction. Diagram B — Compression. Diagram C — Ignition. Dia- 
gram D — Working Stroke. Diagram E — Release. Diagram F — 
Scavenging Stroke. 



GAS, OIL AND STEAM ENGINES 61 

lighter in weight since less material is required to resist shocks 
of the explosions. 

Engines with more than four cylinders have "overlapping" 
impulses, that is some cylinder on the engine is always deliver- 
ing power, for before one cylinder reaches the end of the stroke, 
another has fired its charge and has started to deliver power. 
Thus the impulses "overlap" one another, and the result is an 
even and smooth application of power and a minimum of strain 
is imposed on the engine. 

Aeronautical and speed boat engine builders have carried the 
multiple cylinder idea to an extreme because of the nature of 
their work. Eight cylinder aeronautical engines are very com- 
mon and there are several built having sixteen cylinders. The 
latter type of engine gives eight impulses per revolution. To 
avoid a great multiplicity of cylinders, and to save on floor 
space, the great majority of heavy duty stationary engines are 
built double acting, that is an explosion occurs alternately in 
either end of the cylinder. In effect, a double acting cylinder 
is the same thing as a two cylinder single acting engine, as 
it gives twice the number of impulses obtained with a single 
acting cylinder. 

The order in which the events occur in a four stroke cycle 
engine is as follows: 

STROKE 1. First outward stroke of the piston causes a par- 
tial vacuum in the combustion chamber thus drawing a charge 
of combustible gas into the cylinder through the open inlet valve. 
The exhaust valve is closed. See diagram A in Fig. 4. (Suction 
Stroke.) 

STROKE 2. Inlet valve closes at the end of the suction 
stroke and the piston starts on the inward stroke compressing 
the charge in the combustion chamber. See diagram B. (Com- 
pression Stroke.) At the end of the compression stroke, or a 
little before, the spark "S" occurs causing the ignition of the 
charge. See diagram C. 

STROKE 3. Working Stroke. As the pressure is now estab- 
lished in the cylinder, the piston moves down on the working 
stroke forcing the crank around against the load and supplying 
sufficient energy to the fly wheel to carry the engine through 
the three idle strokes. See diagram D. When the piston reaches 
the end of the working stroke, or a little before, the exhaust 
valve opens to reduce the pressure and to allow the greater part 
of the burnt gas to escape. See diagram E. 

STROKE 4. Scavenging Stroke. The exhaust valve remains 
open and the inwardly moving piston expels the remainder of 



62 GAS, OIL AND STEAM ENGINES 

the burnt gas through the exhaust valve, clearing the cylinder 
for the next fresh charge of mixture. See diagram F. The 
next stroke is the suction stroke explained under "Stroke 1." 

In all of the diagrams the crank is supposed to turn in a 
right handed direction as indicated by the arrow, the piston 
moving in the direction shown by the arrow under the piston 
head. The valves are operated by cams on an intermediate 
shaft known as the "cam shaft." As the valves go through 
their series of movements in two revolutions of the crank shaft, 
and as the cam shaft must perform all of these operations in one 
revolution, it is evident that the cam shaft must run at exactly 
one-half the crank-shaft speed. This change of speed is accom- 
plished by means of gearing between the cam shaft and crank- 
shaft from which the cam shaft is driven. 

In some engines, notably the Diesel engine, pure air is drawn 
into the cylinder on stroke No. 1 instead of the entire mixture. 
Fuel is supplied in this type immediately after the end of the 
compression stroke. 

While an electric spark is shown as the igniting medium in 
the diagrams, the ignition is sometimes performed by a hot 
tube, or simply by the heat of the compression as in the Diesel 
engine. 

In the sliding sleeve type of four stroke cycle motor, the 
poppet -or lifting type of valve as shown in Fig. 4, is replaced 
by a peculiar type of slide valve similar in action to the slide 
valves used on steam engines, except that it is cylindrical in 
form and entirely surrounds the piston. While there is a change 
in the form of the valve, and in a number of small details, the 
gases are drawn into the cylinder, compressed, ignited, and re- 
leased in exactly the same way and in the same rotation, as 
in the poppet valve engine just described. A description of the 
Knight engine which is the most prominent example of the slide 
sleeve motor will be found in a succeeding chapter. Since the 
success of the slide valve type has been acknowledged by many 
prominent automobile manufacturers, there have been several 
similar types placed on the market, some with two sleeves and 
some with one, but in all cases the designers have had but two 
points in view, that is quiet running and free passages. 

(26) Two Stroke Cycle Engine. 

Two stroke .cycle engines perform the five events of aspiration 
(suction), compression, ignition, expansion and release in two 
strokes or one revolution. Providing that these events are per- 



GAS, OIL AND STEAM ENGINES 



63 



formed as efficiently as in the four stroke cycle engine, it is 
evident that with equal cylinder capacity, the two stroke cycle 
engine would have twice the output of a four stroke cycle since 
it gives twice the number of impulses per revolution. Un- 
fortunately it is impossible to attain twice the output of the 
four stroke cycl^ type with the small two stroke engines built 
at the present time because of their imperfect scavenging and 
poor fuel economy. In the larger two stroke engines, the pumps 
and blowers used for scavenging the cylinders consume a con- 
siderable percentage of the output. 

A general classification of the two stroke cycle engine is not 
so simple a matter as that of the four stroke because of the 



IGNITION -CYLINDER 
SUCTION - CRANK-0*S£ 



Diagr am A. 

FIR5T -STROKE 




Diagram B. 

FIRST STROKE 



Diagram C. 

SECOND STROKE. 



Fig. 5. 



Diagram of Two Port — Two Stroke Cycle Engine, Showing the 
Events in the Crank-Case and Cylinder. 



differences in construction of large and small sizes. This dif- 
ference between the large stationary engine and the small type 
commonly used on boats is due to the efforts of the builders 
of the large engine to obtain great fuel economy, while the 
chief endeavors of the builders of small engines is to build a 
simple and reliable engine for the use of inexperienced persons. 
While the smaller type of two stroke engine (less than 25 horse- 
power) has not been used in stationary practice to any extent, 
owing to the defects just named, or on automobiles, it has been 
widely used on motor boats, a service for which it is peculiarly 
adapted. Its extended use on boats is due to the fact that in 
such service it runs at practically a constant speed and works 



64 GAS, OIL AND STEAM ENGINES 

against a steady load, the conditions that are most favorable to 
the type. With automobiles where the motor speed is constantly 
varying, as well as the load, this type of motor is not flexible 
enough to meet the continually varying conditions. 

The small two stroke motors are divided into two principal 
classes, the two port and three port type, depending on the 
method by which the charge is transferred to the cylinder. No 
valves are used in the cylinders of either type for the admis- 
sion or release of the gases. As the two strokes of the cycle 
are the compression stroke and working stroke, it is evident 
that the charge must be introduced into the cylinder by means 
other than by the suction of the piston and at a time when there 
is no pressure in the cylinder. This is accomplished by a pre- 
liminary compression of the charge in the crank case which 
places the mixture under sufficient pressure to force it into the 
cylinder at the end of the working stroke and at the same time 
to displace the burnt gases left from the previous explosion. It 
should be noted that the incoming mixture is a substitute for 
both the suction and scavenging strokes of the four stroke cycle 
engine. 

A diagrammatic view of a two port, two stroke cycle engine 
is shown by Fig. 5, in which P is the piston, C the crank case, 
I the transfer port, V the inlet valve, E the exhaust, and S the 
spark plug for igniting the charge. It should be noted that 
there are no valves in the cylinder and only three moving ports. 
The cycle of events for the two port type is as follows: 

STROKE 1. We will consider the piston to be moving up on 
the compression stroke as shown in view (A), compressing the 
mixture in the combustion chamber D. While moving upwards 
in the direction of the arrow, the piston creates a vacuum in 
the crank case C drawing fresh mixture into the crank case. 
The piston at this time is covering the opening of the transfer 
port I and the exhaust port E so that the compressed mixture 
in the cylinder cannot escape. On reaching the end of the com- 
pression stroke, a spark occurs at S which drives the piston 
down and turns the crank towards the right as shown by the 
arrow. 

STROKE 2. When the piston uncovers the exhaust port E on 
its downward working stroke as shown by view B, the exhaust 
gases being under pressure rush out into the atmosphere as 
shown by the arrows, and relieve the pressure in*the cylinder. 
Some of the burnt gas remains in the cylinder at atmospheric 
pressure as there is no scavenging action up to this point. While 
the piston has moved down on the working stroke it has com- 



GAS, OIL AND STEAM ENGINES G5 

pressed the mixture in the crank case ready for admission to 
the cylinder. The valve V prevents the escape of the gas dur- 
ing the compression. 

On reaching the end of the stroke the piston uncovers the 
transfer port which allows the compressed mixture in the crank 
case to rush into the cylinder through I, as shown by view C. 
Owing to the shape of the deflector plate Z on the piston head, 
the stream of mixture issuing from I is thrown up toward the 
top of the cylinder, as shown by the arrows, and consequently 
sweeps the remainder of the burnt gas before it through the 
exhaust port E. In this way the fresh mixture from the crank 
case scavenges the cylinder and fills it in one operation. Being 
filled with gas, the piston now moves up on the compression 
stroke for the next explosion as shown by view A. 

Unfortunately the scavenging action of the incoming gas is 
not complete for the whirling motion of the charge causes it 
to mix with the residual gas to a certain extent which, of course, 
reduces the heating effect of the fuel and reduces the power 
output. Another factor that reduces the output of this type 
of engine is the loss of explosive mixture through the ex- 
haust port at low engine speeds with an open throttle. In 
this case, the piston speed being low, part of the mixture has 
.time to pass over the deflector plate and through the exhaust 
opening before the piston closes the exhaust port. At very 
high speeds the charge is diluted by a considerable quantity of 
burnt gas which has not had time to escape through the port 
causing a further loss of power. With the throttle nearly 
closed on a light load, the impact of the incoming mixture is 
so slight that the percentage of exhaust gas left in the cylinder 
is very high. This dilution is so great that with moderately 
low speeds (easily within the capacity of the four stroke cycle 
engine) it is either impossible to ignite the charge or it is im- 
possible to ignite two in succession. 

In marine service where the loads are constant, and the 
speeds fairly uniform, there is but little trouble from the last 
mentioned source, and as the fuel is usually a smaller item 
than the repair bill, the simplicity of the small two stroke en- 
gine with its freedom from mechanical troubles usually gives 
satisfactory results in the hands of the novice. 

(27) Three Port— Two Stroke Cycle Engine. 

The principal difference between the three port and two port 
types of the two stroke cycle engine is in the manner in which 



66 



GAS, OIL AND STEAM ENGINES 



the charge is admitted to the crank case for the initial compress- 
ion. In the two port motor, as previously described, the check 
valve "V" opens to admit the charge, and closes during its com- 
pression in order to prevent its escape through the opening 
by which it was admitted to the cylinder. With the three port 
type there is no check valve in the crank case, the admission 
and the retention of the charge being controlled by the move- 
ment of the piston in practically the same way that the piston 
controls the opening and closing of the exhaust and transfer 
ports in the cylinder. 




Figs. 6-7. 



Diagram of Three Port— Two Stroke Cycle Engine in Two 
Positions. 



By the piston control of the gases in the crank case, the valve 
is eliminated, which makes one less moving part to cause trou- 
ble and expense, and permits the use of the same type of car- 
buretor that is used on the four stroke cycle engine. As the 
check valve opens and closes at a high speed, (twice that of the 
valves on a four stroke cycle engine), there is considerable 
wear on the valve seats due to the continuous banging, which 
results finally in a loss of the initial compression. When the 
initial compression is reduced in this way the_ engine loses 
power because of the reduction of the charge in the cylinder. 

While the three port type is free from valve leakage troubles, 



GAS, OIL AND STEAM ENGINES 



67 



it has a steady loss due to the high vacuum that exists in the 
crank chamber when the piston is on its upward stroke. This 
vacuum drags against the piston and absorbs a considerable 
amount of power until the piston reaches the upper end of 
the stroke. At this point the inlet port is opened and the 
vacuum is broken by the rush of the mixture through the in- 
let port. Besides the power loss, the vacuum has a bad effect 
on the lubrication of the main crank shaft bearing. 

Described by strokes, the cycle of events in the three port, 
two stroke cycle engine is as follows: 




Elevation of Fairbanks-Morse Three-Port Two Stroke Marine Motor Show- 
ing Warming Device for Carburetor Air. 

STROKE 1. In Fig. 6, the piston is shown at the end of the 
compression stroke with ignition taking place in the combustion 
chamber C. The pressure due to the expansion drives the piston 
down on the working stroke at the same time causing the initial 
compression of the mixture in the crank case as shown by Fig. 
7. The gas in the crank case cannot escape during compression 
as the inlet port A is covered by the piston. 

(a) As the piston descends, its upper edge uncovers the ex- 
haust port D, allowing the greater portion of the exhaust gases 
to escape and reduces the pressure in the cylinder to that of 
the atmosphere. 



68 GAS, OIL AND STEAM ENGINES 

(b) Descending a little farther, the top of the piston uncovers 
the opening of the transfer port B, allowing the compressed 
gases in the crank case to enter the cylinder as shown by the 
arrows. These gases, guided by the deflector plate on the top 
of the piston are thrown upwardly, as shown by the arrows, and 
sweep the residual burnt gases before them through the exhaust 
port. The cylinder is now filled with the combustible mixture 
ready for compression. 

STROKE 2. The piston now moves up on the compression 
stroke, compressing the charge in the cylinder and at the same 
time creates a vacuum in the crank-case. Just before the piston 
reaches the end of the exhaust stroke, the lower edge of the 
piston uncovers the inlet port A (See Fig. 7), which allows the 
mixture from the carburetor to flow into the partial vacuum 
and fill the crank case ready for the next initial compression. 
When the end of the stroke is reached, the charge in the com- 
bustion chamber C is fired and the cycle is repeated. It should 
be noted that the incoming gas and the initial compression are 
controlled entirely by the action of the lower edge of the piston 
on the inlet port A . 

(28) Reversing Two Cycle Motors. 

As the admission and exhaust in the two stroke cycle engine 
each occur once per revolution, and are controlled directly by 
the piston position at opposite ends of the stroke, it is evi- 
dent that the direction of rotation is not affected by gas con- 
trol or valve timing, as in the case of the four stroke cycle en- 
gine. The factor that does determine the direction of rotation 
in the two stroke engine is the time at which ignition occurs 
in regard to the angular position of the crank. By changing 
the relation between the crank position at the end of the com- 
pression stroke and the time at which the spark occurs, it is 
possible to reverse the engine even when it is running. 

Should the engine be standing still in the position shown by 
Fig. 6, with the crank on the dead center, when ignition oc- 
curred, there would be no more tendency to turn the crank 
to the right than to the left, providing of course, that there was 
no effect from the momentum of a revolving fly wheel. If igni- 
tion occurred with the crank inclined ever so little toward the 
right, the pressure of the piston would force the crank down- 
wards in a right handed direction. If the crank were inclined 
to the left, the tendency would be for left handed rotation. 

If the ignition system were arranged so that the spark oc- 



GAS, OIL AND STEAM ENGINES 



69 



curred when the crank was inclined towards the right every 
time that the piston came up on the compression stroke, we 
should have continuous rotation in a right hand direction. By 
shifting the sequence of the spark so that it occurred with the 
crank on the left we would cause the engine to stop and re- 
verse to left handed rotation. This is exactly the method used 
in reversing two stroke motors in practice, the change in the 



CYLINDER HEAD 



WATER BY PASS 
TO CYLINDER HEAD 



WATER BY PASS 
TO MANIFOLQ 
WATER JACKET- 
INLET AND EXHAUST 
MANIFOLD 

EXHAUST PORT 



TRANSFER PORT 
PISTON RING. 

PISTON. PIN 
PISTON FIN BUSHING 
OIL GROOVE 




CONNECTING 
|*0D BUSHING 
(UPPER HALF - 

Slower half ■ 



■OIL DUCT FROM 
OIL RING TO CRANK 

LOWER CRANK CASE 
CONNECTING ROD CAP 
■OIL SCOOP 



Fig. F-9. Cross Section of Fairbanks-Morse Three Port— Two Stroke 
Cycle Engine, with Parts Named. 

ignition being accomplished by advancing or retarding the 
mechanism that dispatches the spark ("Timer" or "Commu- 
tator"). 

This is an advantage not possessed by the four stroke cycle 
engine of the ordinary type, as the cams and valve mechanism 
require reversal as well as a reversal of the ignition system. 
This relation between the valve action and rotation in a four 
stroke cycle engine may be illustrated by the following example. 



70 GAS, OIL AND STEAM ENGINES 

Consider the piston at the end of the compression stroke in an 
engine designed for right hand rotation. After ignition, under 
the proper conditions, the piston would descend turning the 
crank to the right until it reached the bottom of the stroke, at 
which point the exhaust valve would open and relieve the press- 
ure in the cylinder. 

Let us now consider an attempt at reversing the engine by- 
causing the spark to occur before the piston reached the end 
of the compression stroke with the crank still inclined toward 
the left. In this gase the piston would force the crank down 
in a left hand direction until it reached the end of the stroke. 
The exhaust valve would not open to relieve the pressure, as the 
exhaust cam would be moving away from the valve rod in- 
stead of toward it. Should the crank swing a little past the 
dead center, because of its momentum, the inlet valve would be 
opened instead of the exhaust, and the contents of the cylinder 
would shoot through the intake pipe and carburetor. This 
would bring matters to a close as far as rotation was concerned. 

The opening of the inlet valve on the reversed working stroke 
would occur as the inlet valve closes one stroke, or one-half 
revolution, before the end of the compression stroke. As the 
engine turned backward one-half revolution, the inlet cam would 
again be brought into contact with the inlet valve rod, opening 
the valve and allowing the burned gases to pass through the 
carburetor. Should the pressure be sufficiently reduced by in- 
let valve to allow the piston to reach the end of the second 
stroke, it would start on the third stroke by inhaling a "charge" 
of burnt gas through the exhaust valve which would now be 
open. 

(29) Scavenging Engines. 

As the piston does not sweep out all the cylinder volume be- 
cause of the space left at the end of the cylinder for compression, 
more or less burned gas remains in the combustion chamber 
which dilutes the active mixture taken in on the suction stroke. 
Not only are the residual gases useless in generating heat but 
they also occupy a considerable space in the cylinder that might 
otherwise be filled with a heat producing mixture. Their dilut- 
ing effect also prevents the complete combustion of a certain 
percent of the fuel actually taken into the cylinder for which 
the burnt gas is incapable of supporting combustion. 

The amount of burnt gas remaining in the cylinder depends 
upon the cycle of the engine and also upon the valve timing 



GAS, OIL AND STEAM ENGINES 71 

and size of the exhaust piping. In the four stroke cycle en- 
gine the volume of residual gas is equal to the volume of the 
combustion chamber, in the two stroke cycle it varies from 
one-tenth to one-third of the entire cylinder volume, depend- 
ing on the load and speed. With correct design and free ex- 
haust passages, the gas held in the clearance space of a four 
stroke cycle engine is at a pressure considerably below that 
of the atmosphere, and consequently its actual volume is even 
less than the volume of the combustion chamber. 

Many systems have been devised for the purpose of clear- 
ing the cylinder of burnt gas in order to minimize the loss of 
fuel in large engines, but owing to their complication have never 
been successfully applied to small engines of the automobile 
or marine types. In general, the "scavenging" is accomplished 
by pumping out the clearance space at the end of the scaveng- 
ing stroke, while fresh air is admitted to the cylinder through 
the inlet valves, or by blowing out the clearance -space by a 
blast of pure air furnished from an air pump attached to the 
engine. 

There have been several systems proposed by which the gas 
in the cylinder is withdrawn by the inertia of the exhaust gas in 
specially designed ejectors, and by the compression of fresh air 
in the crank case of the engine. The former system known as 
"organ pipe ejection," is by far the simplest method of all as 
the ejector is simply a tube without moving parts, and it also 
possesses the additional advantage of reducing the back press- 
ure on the piston. Unfortunately these advantages are obtained 
only at certain loads, and with certain velocities of the exhaust 
gases, which makes it impossible to obtain even approximately 
correct scavenging at other loads and speeds. 

When air pumps are used for scavenging, a great percentage 
of the economy obtained is offset by the power required to 
operate the pumps. In addition to the frictional losses of the 
pumps, are the increased maintenance charges and repair bills. 



CHAPTER IV 
INDICATOR DIAGRAMS 

(35) General Description. 

A brief description of the indicator as a means of recording 
the pressures in the cylinder of a simple heat engine in relation 
to the piston position was given in paragraph (6), Chapter I, 
and as this instrument is so peculiarly adapted to locating the 
events taking place in the cylinder we will devote some space 
on its application to the practical gas engine cycles described 
in the preceding chapter. Since each event in the cycle is ac- 
companied by a corresponding increase or reduction in pressure, 
the beginning or end of an event will be indicated on the dia- 
gram by a change in the vertical height of the curve above 
the atmospheric line, at some particular piston position. The 
piston position will be in the same relation to the total stroke 
as the pencil position will be to the horizontal length of the 
card. 

If the event, for example, as indicated by a drop in pressure, 
be at the center of the card, it will show that the drop in 
pressure took place when the piston was in the center of the 
cylinder or at mid-stroke. Should the pressure change at a 
point one-quarter of the card length from the starting point of 
the pencil, it shows that the event took place in the cylinder 
when the piston had accomplished the first quarter of its stroke^ 
and so on. It should be noted that horizontal distances on thfc 
indicator card denote piston positions, and the vertical dis- 
tances, pressures. 

As explained in a former paragraph the length of the vertical 
lines represents certain definite pressures, each inch of length rep- 
resenting so many pounds as per square inch, the exact amount 
per inch depending on the indicator spring strength or adjust- 
ment. To make this point clear, all of the indicator diagrams 
shown in this chapter will be provided with a scale of pressures 
at the left of the diagram by which the pressure at any point 
may be accurately measured off for practice. It should be noted 
that points on the curves which are above the atmospheric line 

72 



GAS, OIL AND STEAM ENGINES 73 

represent positive pressures above the atmosphere, and that the 
points lying below the atmospheric line represent partial vac- 
uums which may be expressed as being so many pounds per 
square inch below the atmosphere. The vacuum pressures in- 
dicate the extent of the "suction" created by the piston when 
drawing in a charge of air and gas. 

Straight vertical lines show that the increase of pressure along 
that line has been practically instantaneous in regard to the pis- 
ton velocity, for if the pressure increased at a slow rate this 
line would be inclined toward the direction in which the pis- 
ton was moving, as the piston would have moved a considerable 
distance horizontally while the pencil was moving vertically. 
This inclination of the vertical line gives an idea of the rate at 
which the pressure increases in relation to the piston speed, 
the greater the inclination, the slower is the rate of pressure in- 
crease. Straight horizontal lines that lie parallel to the at- 
mospheric line denote a constant pressure or vacuum. 

The rate at which horizontal lines descend or incline to the 
atmospheric line represents the rate at which the pressure in- 
creases or decreases, in respect to the piston position (not piston 
velocity). A steep curve represents a rapid expansion or com- 
pression from one piston position to the next. A waving or 
rippling line indicates vibration due to valve chattering or 
explosion vibrations. A straight inclined line shows that the 
pressure is decreasing or increasing in direct proportion to the 
piston position. 

(36) Diagram of Pour Stroke Cycle Engine. 

By referring to paragraph 25, Chapter III, it will be seen 
that the five events of suction, compression, ignition, expansion 
and exhaust are accomplished in four strokes, in the following 
order: 

Stroke 1. Suction — (Mixture drawn into cylinder). 

Stroke 2. Compression — (Mixture compressed). 

St k ^ 1 Ignition. 

* | Expansion (working stroke). 

Stroke 4. Exhaust — (Scavenging stroke). 

These events with the pressures incident to each drawn to 
some relative scale are shown graphically in Fig. 10 by four 
lines representing the four strokes of the piston. In order to 
show the relation between the diagram and the piston, a sketch 
pf the cylinder with a stroke equal to the length of the dia- 
gram is shown directly beneath the curve. The vertical line IJ 



74 



GAS, OIL AND STEAM ENGINES 




Figs. 10-11-12. Showing Respectively a Typical Four Stroke Diagram, 
Retarded Combustion and Retarded Spark. 



GAS, OIL AND STEAM ENGINES 75 

is the scale of pressures (somewhat exaggerated in order that 
the small vacuum and scavenging pressures shall be clearly 
shown). The line marked "atmosphere" represents atmospheric 
pressure and it is from this line that all measurements of 
pressure are taken. 

Consider the piston starting on the suction stroke, the piston 
moving from the position L to K, or from left to right. The 
movement creates a partial vacuum in the combustion chamber 
N which is shown on the diagram as the distance OA, equal to 
2 pounds below atmosphere according to the pressure scale. 
The suction line remains at this distance below the atmospheric 
line until within a short distance of the end of the stroke when 
it rises to meet the atmospheric line at B when the piston 
reaches the end of the stroke at K. This rise at the end of the 
stroke is due to the fact that the piston moves more slowly 
when approaching the end of the stroke while the velocity of 
the incoming gases remains nearly constant so that the piston 
exerts no pull nor suction. On the diagram the entire suction 
stroke is represented by AB. 

The piston now returns on the compression stroke from K to 
J compressing the mixture in the combustion chamber N. On 
the diagram this stroke is shown beginning at B, with the pres- 
sure slowly rising until the pressure is a maximum at the point 
€ at the end of the stroke. During the compression, the pres- 
sure has risen from that of the atmosphere at B to 125 pounds 
pressure at C as shown by the scale. At a point slightly before 
C is reached, ignition occurs, and the pressure rapidly rises from 
C to D, due to the expansion of the heated gas. In this case 
the combustion is practically instantaneous as shown by the 
straight, vertical combustion line CD. 

At D the piston starts on the working stroke from left to 
right increasing the volume of the gas and at the same time di- 
minishing the pressure because of the expansion until the maxi- 
mum pressure of 400 pounds per square inch at D is reduced to 
30 pounds per square inch at E, the line DE being called the ex- 
pansion line. During this time the heated gas has been perform- 
ing work on the piston. At E the exhaust valve opens and the 
pressure drops from E to T, a point still about 10 pounds above 
atmospheric pressure. Theoretically the pressure should drop 
instantly from E to atmosphere, or from 30 pounds per square 
inch to zero, but practically this is impossible because of the 
back pressure due the slow Escape of the exhaust gases through 
the comparatively small valve openings and exhaust pipes. 



76 GAS, OIL AND STEAM ENGINES 

Since considerable pressure is exerted by the piston on the 
return stroke in forcing the gases out of the exhaust valve, the 
exhaust line TO on the diagram is nearly 10 pounds above the 
atmospheric pressure from T to O. At a point near O, the 
piston slows up on nearing the end of the stroke so the gases 
have more time to escape through the valves, and the pressure 
drops to the atmosphere, reading for the succeeding suction 
stroke. 

It should be noted that the points A, B, E, and F represent 
periods of valve action. At A the inlet valve opens; at B 
the inlet closes; at E the exhaust opens; at F the exhaust closes, 
and at A the inlet again opens at the beginning of the suction 
stroke AB. That this is true is apparent from the fact the 
inlet must open at the beginning of the suction stroke, and 
both valves must be closed from the point B to the point E 
in order to prevent the escape of the compressed charge and 
expanded gases from the cylinder. At the end of the working 
stroke the exhaust valve must liberate the gases and remain 
open to the end of the scavenging stroke to eliminate the 
residual gas while the closed inlet valve prevents the burnt gases 
from being forced through the inlet pipe and carburetor. 

As shown on the diagram, the exhaust valve closes at the 
same time that the inlet opens, as F, and O both occur on the 
same vertical line DL. This is true theoretically, but owing to 
the different conditions met in practice, the actual setting of 
the valves may vary slightly from that shown on the diagram. 
Some makers of high speed engines open the inlet slightly be- 
fore the exhaust closes as it is claimed that the inertia of the 
exhaust gas passing through the exhaust pipe creates a slight 
vacuum that is an aid in filling the cylinder with a fresh charge. 
It should be borne in mind that this condition only exists when 
the piston has come to rest and exerts no pressure on the 
exhaust gas. The vacuum is due to the velocity inertia of the 
gas after it has been reduced to atmospheric pressure. Other 
makers close the exhaust valve a very little before the inlet 
opens, but no matter what the setting, the difference in the time 
of opening and closing is very small, and the results obtained 
probably differ by an almost negligible amount. 

During the suction and scavenging strokes, the fly wheel of 
the engine is expending energy on the gas since it is moving 
a considerable volume at a fairly high pressure. In the case 
of the scavenging stroke, the piston is working against 10 
pounds back pressure, which on a 10 inch piston would amount 



GAS, OIL AND STEAM ENGINES 77 

to a force of 785 pounds. With the 2 pound vacuum the drag 
on the piston would amount to 157 pounds, no small item when 
the velocity of the piston is considered. Of course the pressure 
of 10 pounds per square inch is rather high, but it is often at- 
tained with long and dirty exhaust pipes. It is items of this 
nature that cut into the efficiency of the engine, and increase 
the fuel bills, and it is only by the indicator that we can de- 
termine the extent of such "leaks" and remedy them. 

Since the area of the indicator card represents the power of 
the engine, it is evident that we lose the power represented by 
the area included in the rectangle FEBO on the scavenging 
stroke plus the area BOA on the suction stroke. The area in- 
cluded in BCO represents the work taken from the engine in 
compressing the charge, but this is returned to us during the 
next stroke plus the benefits gained by compressing the mix- 
ture. The arrows show the direction in which the piston is 
moving during that event. 

An actual engine does not follow the form of the diagram 
shown by Fig. 10 exactly because of certain conditions met with 
in practice such as imperfect mixtures, faulty valve and ignition 
timing, small valve areas or leakage. The combustion in the real 
engine is neither instantaneous nor complete but it approximates 
the "IDEAL" cycle just described more or less closely with a 
high compression and a fairly well proportioned mixture. 

(37) Detecting Faults With the Indicator. 

For the best results the gas must be completely ignited at the 
point of maximum compression, and the pressure must be estab- 
lished on the dead center, so that the indicator card will show 
a straight and vertical combustion line. As all gases require a 
certain length of time in which to burn, the ignition should 
have LEAD, that is, should be started before the end of the 
stroke so that combustion will be complete at dead center. The 
amount of ignition lead required depends on the fuel and the 
compression. In Fig. 10 the point of ignition (I) is shown as 
occurring before the end of the compression at (C), which 
insures a straight combustion line CD. 

With a lean or slow burning gas, that is, a gas slower than 
used on the diagram, combustion would not be complete at the 
end of the stroke if the same point of ignition were used. This 
effect is shown by Fig. (11), in which the full line diagram BCDE 
represents the ideal diagram (Y), and BCFG represents the 
slow burning mixture with the same point of ignition (X). 



78 



GAS, OIL AND STEAM ENGINES 



The compression curves of both diagrams are coincident as 
far as C, the ideal diagram shooting straight up at this point 
and the weak mixture diagram staying at the same level. When 
under the influence of the mixture (X) the piston starts from 
left to right and reaches the point F before the slow burning 
gas reaches its maximum pressure. During this part of the 
stroke there has been very little pressure on the piston and it 




c\ 


- — e- 


4, 


♦ 






\ 


Fvsu&a /4 






\ 






L/ 


V \ 


^ 



// 



Figs. 



13-14. The First Diagram (13) Shows a Two Port Two Stroke 
Diagram, the Second Shows a Typical Diesel Card. 



will be noticed that the maximum pressure is far below that of 
the ideal diagram. This low maximum is due principally to 
the reduced compression under which the gas has been burn- 
ing, from C to F. 

As the gas has but a small part of the stroke left in which 
to expand, the pressure at the point of release is much higher 
than the release pressure of the ideal diagram, which means 
that a considerable amount of heat and pressure have been 
wasted through the exhaust pipe. Besides the heat loss, the 



GAS, OIL AND STEAM ENGINES 7!) 

high temperature of the escaping gas has a bad effect on the 
exhaust valve and passage. The great volume of gas passing 
through the exhaust valve also increases the back pressure on 
the scavenging stroke. 

Delayed or retarded ignition will cause a low combustion 
pressure and slow combustion with any type of fuel or compres- 
sion pressure as will be seen from Fig. 12. In this case the 
compression pressures of the ideal diagram Y and the dia- 
gram X showing the retarded spark are of course the same, 
the compression line extending from B to C in the direction of 
the arrows. At C the ignition occurs for curve Y, and the 
pressure immediately rises to D. In the case of curve X, igni- 
tion does not occur until the point I is reached, the compres- 
sion falling on the line CI with the forward movement of the 
piston as far as the point I. At this point the compression 
pressure is very low which results in the slow combustion in- 
dicated by the slant of the combustion line IF. The point of 
maximum pressure F is much below D of the. ideal curve, and 
as there is no opportunity for complete expansion during the 
rest of the stroke, the release pressure is high causing a great 
heat loss. If running on a LATE or RETARDED spark is 
continued for any length of time the excessive heat that passes 
out of the exhaust will destroy the valves. 

It is apparent that for the best results, the spark should occur 
slightly before ignition in order to gain the effects of the com- 
pression, and a high working pressure on the piston. It is also 
evident that the point of ignition should be varied for different 
mixtures that have different rates of burning. With engines 
that govern their speeds by throttling or by changing the 
quality of the mixture it is necessary for the best results, to vary 
the point of ignition with each quality of fuel that is admitted 
by the governor. The retard and advance of the ignition is very 
necessary on an automobile engine because of the throttling 
control and constant variation of the load and speed. All auto- 
mobilists know of the heating troubles caused by running on 
a retarded spark. 

(38) Two Stroke Cycle Diagram. 

In the two stroke cycle diagram, the lines showing the suc- 
tion and scavenging strokes are missing if the indicator is ap- 
plied* only to the working cylinder. 

Starting at the beginning of the working stroke as at A in 
Fig. 13, the gas expands during the working stroke until the 



80 GAS, OIL AND STEAM ENGINES 

piston uncovers the exhaust port at B where the pressure drops 
to C. A slight travel uncovers the inlet port with the pressure 
still above atmosphere due to the pressure in the crank case 
filling the cylinder. The crank case pressure continues from 
C to D or to the end of the stroke, the pressure dropping 
slightly at the latter point. 

The compression stroke now takes place with the piston 
moving from right to left, the compression pressure reaching 
a maximum at F. Ignition occurs slightly before the point of 
greatest compression, at I, and the expanded gas increases in 
pressure until the point A is reached. From this point the 
same cycle of events is repeated. Because of the dilution of 
the charge by the burnt gases of the preceding combustion, the 
mixture burns slowly as will be seen from the inclined combus- 
tion line FA. Due to this delayed combustion, the piston travels 
the distance S on the working stroke before the pressure reaches 
a maximum, This diagram is typical of the small marine type 
of two stroke cycle engine which has no further scavenging 
than that performed by the rush of the entering mixture. The 
diagram of the pressures and vacuums in the crank case are 
similar to those of suction and compression in the four 
stroke cycle type. 

(39) Diagram of Diesel Engine. 

A diagram of the Diesel engine is different in many par- 
ticulars from that of an ordinary gas engine, as will be seen 
from the diagram in Fig. 14. The pressures rise in an even, 
gradual line from the end of the compression curve, and in- 
stead of having a sharp peak at the end of the combustion, 
as in a gas engine, the top of the curve is broad and greatly 
resembles the indicator diagram of a steam engine. The com- 
pression curve constitutes a greater proportion of the pressure 
line than that of a steam engine, the rise of pressure due to 
the ignition being very slight in comparison to the height of 
the compression curve. There is no explosion in the usual 
sense of the word, only a slight increase in pressure as dis- 
tinguished from the rapid combustion in the gas engine. 

Starting at the beginning of the compression stroke at H, the 
pressure of the pure air charge increases to about 500 pounds 
to the square inch at I, the point at which the fuel is injected. 
From I to C is the increase of pressure due to the combustion. 
The pressure stays at a constant height from C to D as the fuel 
supply is continued between these points, and is cut off when 



GAS, OIL AND STEAM ENGINES 81 

the piston reaches the position D. It will be seen that the 
admission of the fuel through the distance A covers a consider- 
able proportion of the working stroke, and that the points of 
fuel injection and ignition are coincident. 

From the point of fuel cut-off at D expansion begins and is 
continued in the usual manner to F, the point of release. 

When the load is increased, the period of oil injection is also 
increased, the other events remaining constant. Should the 
light load require an oil injection period as shown by A, the 
greater load would require injection for the period B. In the 
latter case, the expansion line would be E G, which would pro- 
duce a diagram having a greater area than the line DF, and 
there would be a great increase in the release pressure GH as 
well. 

It will be seen from the diagram that the quantity of air 
taken into the cylinder and the compression pressure remain 
constant with any load, and that for this reason it is possible 
to have a constant point of ignition, or rather point of fuel 
injection. As there is no mixture compressed, there are no dif- 
ficulties encountered at light loads due to attenuated mixtures. 
An excess of air over that required to burn the fuel is also 
present at every load within the range of the engine. For the 
sake of simplicity, the suction and scavenging lines on the 
Diesel engine have been omitted, but they are the same in all 
respects as the corresponding" lines shown in the diagram, 
Fig. 14. 

(40) Gas Turbine Development. 

In the attempt to gain mechanical simplicity, small weight, 
and diminutive size of the steam turbine, many able experi- 
menters have endeavored to obtain an internal combustion 
motor in which the energy of the expanding gas is converted 
into mechanical power by its reaction on a bladed wheel, but 
so far the problem is far from being solved. In 1906 two ex- 
perimental turbines were built by Rene Armengand and M. 
Lemale, of the constant pressure type, one of which developed 
30 Brake horse-power and the other 300 horse-power. 

A 25 horse-power De Laval steam turbine was altered by 
Armengand says Dugald Clerk so that it operated with com- 
pressed air instead of steam. The compressed air was passed 
into a combustion chamber together with measured quantities 
of gasoline vapor, and the mixture was ignited by an incan- 
descent platinum wire as it entered the chamber, thus maintain- 



82 GAS, OIL AND STEAM ENGINES 

ing a constant pressure with continuous combustion. Around 
the carborundum lined combustion chamber was imbedded a 
coil in which steam was generated by the heat of the burning 
gas, the steam being used to reduce the temperature of the gas 
from 1800°C to about 400° as it issued from the orifice and came 
into contact with the running wheel. The working medium was 
therefore composed of two elements, the products of combus- 
tion "and the steam at the comparatively low temperature of 
400° C. 

The constant pressure maintained in the combustion chamber 
was about 10 atmospheres, and the hot gases were allowed to 
expand through a conical Lava jet in which the expansion pro- 
duced a high velocity, and reduced the temperature of the fluid. 
At this reduced temperature and high velocity the gases im- 
pinged upon the Laval wheel, and rotated the wheel in the 
same way as steam would have done. The experiments showed 
that under these conditions the total power obtained from the 
turbine separate from the compressor was double that neces- 
sary to drive the compressor. 

In the large 300 H. P. turbine the first part of the combus- 
tion chamber was lined with carborundum, backed by sand, 
but the second part was surrounded by a coil through which 
water was circulated. The water kept the temperature of the 
combustion chamber within safe limits, and after absorbing 
heat, it passed also around the jet nozzle, and was discharged 
into the passage leading to the jet, and there converted into 
steam by the hot gases. A mixture of products of combustion 
and steam thus impinged upon the turbine wheel. The ex- 
panding jet was arranged to convert the whole of the energy 
into motion before the fluid struck the wheel; the temperature 
was thus reduced to a minimum before the gases touched the 
blades. Notwithstanding this, the wheel itself had passages 
through which cooling water flowed, and each blade was sup- 
plied with a hollow into which water found its way. In the 
large turbine the compressor was mounted on the turbine 
spindle; it was of the Rateau type, and consisted of an inverted 
turbine of four stages, which delivered the compressed air finally 
to the combustion chamber at a pressure of 112 lb. per sq. in. 
absolute. The efficiency of this turbine compressor was found 
to be about 65 per cent. The total efficiency of the combined 
turbine and compressor was low, as the fuel consumption 
amounted to nearly 3.9 lb. of gasoline per B. H. P. hour. An 
ordinary gasoline engine with a moderate compression can 



GAS, OIL AND STEAM ENGINES 83 

readily give its power at the rate of 0.5 lb. of gasoline per 
B. H. P. hour. The combined turbine and compressor was 
stated to have run at 4,000 R, J*. M. and to have developed 300 
11. I*, over and above the negative work absorbed by the 
compressor. 

A gas turbine in which there was no compression was built 
in the following year by M. Karovodine which gave 1.6 horse- 
power at a speed of about 10,000 revolutions per minute. 

It contained four explosion chambers having four jets actuat- 
ing a single turbine wheel, which wheel was of the Laval type, 
about 6 inches diameter, having a speed of 10,000 R. P. M. The 
explosion chambers were vertical, and had a water jacket sur- 
rounding the lower end. The upper portion contained the 
igniting plug on one side, and the discharge pipe connecting 
with the expanding jet on the other. In the lower water- 
jacketed part there was provided a circular cover, held in place 
by a screwed cap. This circular plate was perforated with 
many holes, and it carried a light steel plate valve of the flap 
or hinging type, which pulled down by a spring contained within 
the admission passage. This spring could be adjusted, and the 
lift of the valve was. regulated by means of a set screw passing 
diagonally through the water jacket. Air was admitted at 
one side by a pipe leading into the valve inlet chamber and a 
corresponding passage or pipe admitted gasoline and air or gas 
to mix with the air before reaching the thin plate valve. Ad- 
justing contrivances were supplied in both air and fuel ducts. 
To start the apparatus, an air blast was forced through the 
valve, carrying with it sufficient gasoline vapor to make the 
mixture explosive. The electrical igniter was started, and the 
spark kept passing continuously. Whenever the inflammable 
mixture reached the upper part of the combustion chamber igni- 
tion took place, and the pressure rose in the ordinary way, due 
to gaseous explosion. The gases were then discharged through 
the pipe and nozzle on the Laval wheel. The cooling of the 
flame after explosion and the momentum of- the moving gas 
column reduced the pressure within the explosion chamber to 
about 2 lb. per sq. in. below atmosphere. Air and gasoline 
vapor then flowed in to fill up the chamber, and as soon as the 
mixture reached the igniter, explosion again occurred. In this 
way a series of explosions was automatically obtained, and a 
series of gaseous discharges was made upon the turbine wheel. 
Diagrams taken from the explosion chamber showed a fall in 
pressure during suction of 2 lb. per sq. in.; ignition occurred 



84 



GAS, OIL AND STEAM ENGINES 



while the pressure was low, and the pressure rapidly rose to 
about 1 1-3 atmospheres absolute. The pressure propelling the 
gas column and jet was thus only 5 lb. per sq. in. above at- 
mosphere. The pressure rapidly fell, and the whole process 
was repeated again. According to the diagrams taken, a com- 
plete oscillation required about 0.026 second, so that about 40 
explosions per second were obtained. 

The most promising type of turbine that has been built to 
date is that designed by Hans Holzwarth, an engineer of 
some prominence in the steam turbine field. A 1000 horse- 




Fig. 15. 



Cross-Section of the Combustion Chamber of the Holzworth 
Gas Turbine. From the Scientific American. 



power machine has been built at this writing and as ex- 
perimental machines go has made most remarkable performance. 
The turbine in general arrangement outwardly resembles the 
Curtis steam turbine, in that the turbine wheel rotates in a 
horizontal plane, the spindle or shaft is vertical and a dynamo 
is mounted on this spindle above the turbine. In the Holzwarth 
turbine ten combustion chambers are provided, each of a pear 
or bag shape. They are arranged in a circle around the wheel, 



GAS, OIL AND STEAM ENGINES 85 

and are cast so as to form the base of the machine. The wheel 
is of the Curtis type, with two rows of moving and one row 
of stationary blades. 

In this turbine the energy of the fuel is liberated intermit- 
tently by successive explosions, instead of by continuous com- 
bustion, and in much the same way that the explosions occur in 
a reciprocating engine. Tests made on the new machine have 
shown that it is in no way inferior in efficiency to the ordinary 
type of motor, and that at full load, the weight per horse-power 
is only about one-quarter of that of the reciprocating engine. 
The weight factor, as is well known, is of the utmost im- 
portance in marine service and should prove of value to the 
marine engineer, if this alone were its only characteristic. 

Any of the ordinary power gases may be used with success, 
as well as vaporized liquid fuels, and the lower grade oils such 
as crude and kerosene have given much better results in the 
turbine, than in reciprocating engines, even at this early stage 
of its development. As the heat losses are much smaller than 
met with in ordinary practice, the temperature is higher, which, 
of course, greatly facilitates the vaporization of the lower grade 
liquids. 

Mr. Holzwarth does not give the dimensions of his turbine 
wheel, but from the drawings and some of the velocities given 
by him it appears to be about 1 m. in external diameter. The 
lower part of each combustion chamber carries gas and air inlet 
valves, and the upper part carries a nozzle arranged to cause 
the gases to impinge upon the first row of moving blades. This 
nozzle is connected to and disconnected from the combustion 
chamber by means of an ingeniously operated valve. The ex- 
plosion chambers are charged with a mixture of gas and air, 
which appears to attain a pressure of about two atmospheres 
within the chamber before explosion. The air and gas are 
supplied under sufficient pressure from turbine compressors, 
actuated by steam raised from the waste heat of the explosion 
and the gases of combustion, so that whatever work is done in 
compression is obtained by this regenerative action, and does 
not put any negative work upon the turbine itself. The com- 
bustion chambers are fired in series, by means of high-tension 
jump spark ignition. 

Referring to the cut, the explosion chamber A is filled in- 
termittently with the explosive mixture at a low pressure (about 
8 to 12 pounds per square inch). When ignition has occurred, 
the pressure of explosion opens the nozzle valve F, allowing 



86 GAS, OIL AND STEAM ENGINES 

the compressed gases to flow through the nozzle G to the bladed 
turbine H, on which the energy is to be expended. The ex- 
pansion of the heated gases in the nozzle reduces the pressure 
to that of the exhaust, with the resulting increase in the velocity 
of the gas. By means of fresh air, the nozzle valve F is kept 
open throughout the expansion and scavenging periods. 

After the expansion has been completed, the air that is forced 
through the valve D, at a low pressure, thoroughly scavenges or 
removes the residual burned gases left in the combustion cham- 
ber and nozzle, forcing it into the exhaust. When the scaveng- 
ing has been completed, the nozzle valve and the air valve D 
are closed. The combustion chamber A is now filled with 
pure cold air, which not only enables a fresh charge of gas to 
be introduced into the chamber but which also aids in keeping 
the chamber cool. 

Pure fuel gas, or atomized oil, is now injected through the 
fuel valve E, forming an explosive mixture ready for the en- 
suing cycle of events. A number of these chambers are ar- 
ranged around the turbine* wheel in order to have a uniform 
application of power, by having the several chambers working 
intermittently. This is in effect, the same proposition as in- 
creasing the number of cylinders on a reciprocating engine. 



CHAPTER V 
TYPICAL FOUR STROKE CYCLE ENGINES 

(41) Essential Parts of the Gas Engine. 

On all gas engines of accepted type are found certain devices 
necessary for the performance of the events or cycles outlined 
in the preceding section. 

For the sake of simplicity these devices are treated as a part 
complete in itself. The details of construction, and the refine- 
ments found necessary in the actual construction will be de- 
scribed in the succeeding chapters. 

The names and purpose of these essential components, and 
their relation to the operation of the engine as a whole, will be 
found in the following outline: 

1. The CARBURETOR is a device whose purpose is to 
vaporize the liquid fuel, and mix the vapor thoroughly and in 
correct proportions with the air required for the combustion, 
in the engine cylinder. 

The combustible mixture thus formed is drawn into the 
cylinder of the four stroke cycle engine or into the crank cham- 
ber of the two stroke cycle engine. 

GENERATOR VALVES or MIXING VALVES are similar 
to the carburetor in principle but are slightly different in detail. 

2. The CYLINDER is the containing vessel in which the 
combustion and expansion of the gas takes place. 

The cylinder as its name would suggest has a circular open- 
ing or bore extending from end to end, the bore being smoothly 
finished to receive the reciprocating piston. 

3. The PISTON is a plunger or movable plug fitting the 
bore closely enough to prevent the escape of gas, but at the 
same time is capable of sliding freely to and fro. 

When pressure is established in the cylinder from the com- 
bustion, pressure is also exerted on the end of the piston tend- 
ing to force it out of the cylinder. The extent of this force is 
governed by the area of the end of the piston and also by the 
pressure of the gas. 

87 



38 



GAS, OIL AND STEAM ENGINES 



Thus the purpose of the piston is to convert the pressure of 
the expanding gas into direct mechanical force, and also to 
transform the increasing volume of gas into motion. Another, 




Piston and Connecting Rod of the Sturtevant Aero Motor, Showing Three 

Piston Rings. 

and no less important function of the piston is to compress the 
combustible gas in the upper end of the cylinder for ignition. 

4. The CONNECTING ROD (Sometimes called the Pit- 
man) transmits the pressure on the piston to the crank, the 
connecting rod being the means through which the to and fro 
motion of the piston is transmitted into the rotary motion of the 
crank; its action being similar to that of the human arm turn- 
ing the crank of a pump or windlass. 

5. The CRANK receives the pressure and motion of the 
piston from the connecting rod, changing the reciprocating mo- 
tion of the piston into the rotary motion required by the 
machinery which the engine drives. 

In the majority of cases the crank revolves, while the cylinder 
stands still, but in some of the recently developed aeronautic 
motors this is reversed, the cylinders revolving with the crank 
stationary. The relative motion, however, is the same in both 
cases. 

(6.) The CRANK SHAFT, of which the crank is an integral 
part, transmits the rotary motion of the crank to the driving 
pulley. 

(7.) The admission and release of the gases to and from the 
cylinder are controlled by the INLET VALVE and EXHAUST 
VALVE, respectively, in a four stroke cycle engine. 

The valves are merely gates, allowing the gas to flow, or 
stopping it, at the proper intervals, depending on the event 
taking place at that time in the cylinder. 



CAS, OIL AND* STEAM ENGINES 89 

In the two stroke cycle engine there are no valves, the ad- 
mission and release of the gas being controlled by the position 
of the piston, and the openings cut in the cylinder walls. 

6. IGNITION or the firing of the combustible charge is ac- 
complished by the IGNITION SYSTEM. In most modern 
engines the mixture is ignited when it is under the greatest 
pressure or at the end of the stroke. 

For maximum efficiency the mixture should be ignited when 
it is under the greatest pressure or compression. The time at 
which ignition occurs is also controlled by the ignition system. 

7. The GOVERNOR regulates the speed of the engine; either 
by changing the richness of the mixture, by changing the num- 
ber of working strokes in a given time or by altering the 
quantity of gas admitted to the cylinder, or sometimes by a 
combination of these methods. 

8. The BELT WHEELS or PULLEYS are the means of 
transmitting the power of the engine to the work to be per- 
formed. The engine is generally connected to the driven ma- 
chinery by a belt connecting the engine pulley with the pulley of 
the driven machine. 

9. The FLY WHEELS by reason of their mass and their 
momentum, store up a portion of the energy expended during 
the working stroke, and return it to the engine in order to carry 
it through the idle strokes of compression, admission and ex- 
pulsion. In some engines the fly wheels serve in double the 
capacity as pulleys. 

10. The BASE or FRAME of the engine acts as a foundation 
for the various working parts, holding them in their proper 
positions. 

(42) Application of the Four Stroke Principle. 

While the five events of every commercial four stroke cycle 
engine are accomplished in exactly the. same order, or routine 
as explained in paragraph (8), Chapter 3, the actual design and 
method of applying the cycle varies greatly in different makes 
of engines. This great difference in the details of construction 
often makes it difficult for the novice to identify the cycle of 
operations in that particular engine. The different forms of 
valve gears that are used to perform the same functions in the 
cycle are good examples of the variation in design, some makers 
using the poppet or disc type, some the sliding sleeve, and others 
the rotary type. 

Multiple cylinder engines vary in the cylinder grouping or 



90 



GAS, OIL AND STEAM ENGINES 




Fig. 16. Ball Bearing Crank Shaft, Pistons and Connecting Rods of the 
Maximotor," in Their Relative Positions. 

arrangement, the arrangement and number of cylinders depend- 
ing on the service for which the engine is intended, the amount 
of vibration permissible, or the weight. The question of speed 
also introduces modifications in the design, but no matter what 
valve arrangement is adopted or what grouping of cylinders is 



GAS, OIL AND STEAM ENGINES ( J1 

used, a four stroke cycle engine performs the five events of 
suction, compression, ignition, expansion and exhaust in four 
strokes, in each and every cylinder. With the exception of fuel 
injection (which in reality corresponds to the ignition event) 
in the four stroke Diesel engine, the indicator cards of all four 
stroke cycle engines passes the same characteristics as the dia- 
gram shown in Fig. 10. 

In this chapter, the engine will be described without regard 
to the fuel used, or to the means adopted in vaporizing it, for 
the vaporizing appliances are considered as being external to 
the engine proper, except in some of the heavy oil engines, and 
as the fuel is gasified before entering the cylinder the question 
of fuel does not affect the general construction of the engine. 
The majority of engines are readily converted from gasoline to 
gars, or in some cases kerosene, by changes in the vaporizing 
device, and with the exception of changing the compression 
pressure, little further alteration is needed. Since the vaporiza- 
tion and admission of the heavier oils, such as crude oil and 
kerosene has a more intimate relation to the engine than the 
use of gasoline or gas, the heavy oil engines will be described 
in a separate chapter in order that the process of oil burning 
may be more fully explained. It should not be understood that 
the cycle, or principle of the oil engine differs from that of any 
other engine, but that the vaporizer forms such a close 
connection with the engine proper that they must be described 
as one unit. 

(43) Horizontal Single Cylinder Engine. 

An example of a modern single cylinder engine operating on 
the four stroke cycle principle is the "Muenzel" engine shown 
in Section by Fig. 17. It is of the single acting type, that is, 
the pressure of the gases acts only on the left end of the piston 
which reciprocates in a horizontal direction. Surrounding the 
cylinder in which the piston slides, is the water jacket (shown 
by the short horizontal dashes) which keeps the cylinder walls 
from becoming overheated by the successive explosions of the 
mixture. The cooling water is pumped into the jacket through 
the pipe shown over the cylinder, and flows out of the jacket 
through an outlet near the bottom of the cylinder. 

Both the inlet and exhaust valves are situated in an ex- 
tended portion of the combustion chamber to the left of the 
piston, the upper valve being the inlet and the lower valve, the 
exhaust. The valves are held on their seats by means of coil 




Fig. 17. Longitudinal Section Through the Muenzel Horizontal Engine. 



GAS, OIL AND STEAM ENGINES 93 

springs that act on the upper ends of the valve springs. Admis- 
sion of the explosive mixture is controlled by the upper valve, 
and the release of the burnt gases by the lower. Pipes at the 
bottom of the cylinder marked "Gas Supply" and "Exhaust" 
convey the gases to and from the inlet and exhaust valves re- 
spectively. 

The inlet valve, and the inlet valve spring are held in one unit 
by a removable metal housing known as a "Valve Cage", which 
is arranged so that the cage, valve, and spring may be re- 
moved as one piece from the cylinder casting when the valves 
need attention by removing a few bolts. As the cage is directly 
over the exhaust valve, and is considerably larger in diameter, 
it is possible to remove the exhaust valve through the opening 










Fig. 18. Elevation of Muenzel Engine Showing Lay Shaft and Valve 

Connections. 

left by the removal of the inlet valve cage. Both valves are 
surrounded by a water jacket, as are the passages that lead to 
them. 

Both the inlet and exhaust valves are opened and closed at 
the proper moments in the stroke by means of cams mounted 
on the horizontal cam shaft shown by Fig. 18 through a system 
of levers. The cam shaft is the shaft running parallel to the 
engine bed from the crank-shaft to the end of the cylinder and 
turns at one-half the speed of the crank-shaft. At a point 
directly below the inlet valve in Fig. 18, will be seen an en- 
largement on the shaft on which rests the rod running from the 
inlet valve to the cam shaft. This is the cam. 

A cylindrical casing shown above the cylinder contains the 



94 GAS, OIL AND STEAM ENGINES 

governor which maintains a constant speed at all loads by oper- 
ating a valve in the intake pipe which varies the quantity of 
mixture entering the cylinder in proportion to the load. The 
governor is driven from the cam-shaft by spiral gears. The 
igniter which furnishes the spark for igniting the gas is located 
between the two valves at the extreme left of the combustion 
chamber (Fig. 17). 

It should be noted that the cylinder head which closes the 
left end of the cylinder, and which carries the valves is separate 
from the main body of the Cylinder. By unscrewing the bolts 
that hold it to the cylinder, the head may be removed when 
it becomes necessary to remove dirt and carbonized oil from 
the combustion chamber, or when it becomes necessary to re- 
move the piston. The cylinder barrel in which the piston 
works may also be removed through the opening left by the 
piston head when it becomes worn, and another barrel or liner 
may be substituted, thus practically renewing the engine at a 
small fraction of the cost of a new cylinder. The liner is 
fastened firmly to the outer cylinder casting at the left but is 
free to slide back and forth in the casting at the right hand end, 
this end being provided with a packed joint. This play given 
to the liner allows it to expand and contract freely with the dif- 
ferent changes of temperature without causing strains either 
in the cylinder or in the liner. 

(44) Multiple Cylinder Engines. 

Since the power exerted by a single cylinder four stroke 
cycle engine is intermittent, the explosive force exerted on each 
power stroke is much heavier than would be the case if the 
power application were continuous, as the explosions must be 
heavier to compensate for the idle periods. To reduce the 
strain on the engine and the vibration as well and to obtain an 
even turning moment it has been customary to provide more 
than one cylinder on engine of over 10 horse-power capacity. 
In this way the total power is divided among a number of 
cylinders, and as no two cylinders are under ignition at any 
one time the turning moment is more even, the vibration is less, 
and the strain on the engine is considerably reduced. 

Dividing the power in this way makes it possible to reduce 
the weight of the engine as less material is required to resist 
the strains and a small fly-wheel may be used because of the 
even engine torque. In order to gain the full benefit of this 
reduction in weight, the builders of aeronautic motors have 



(J AS, OIL AND STEAM ENGINES 95 

carried the multiplication of cylinders to an extreme, the An- 
toinette for example having sixteen cylinders. Engines having 
more than six cylinders exert a continuous pull as the impulses 
"overlap," that is, ignition occurs in one cylinder before another 
cylinder in the series ends its working stroke. The greater the 




Fig. F-12. Six Cylinder Maximotor. 

number of cylinders, the more continuous will be the torgue 
or turning moment. The multiple cylinder engine may be 
considered as a group of single cylinder engines connected to- 
gether, and receiving their fuel from a common source, the only 




Fig. F-13. Four Cylinder Buffalo Motor for Marine Service. 

difference between the single and multiple being in the inlet 
and exhaust piping and the ignition system. 

As a single cylinder four stroke cycle engine has one working 
impulse in every two revolutions, a two cylinder engine will 
have an impulse for every revolution as there are twice as 
many impulses in the same time. It should be remembered 
that the number of impulses' given per revolution by a four 



96 GAS, OIL AND STEAM ENGINES 

stroke cycle engine is equal to the nujnber of cylinders divided 
by two. Thus, a six cylinder engine has 6-^2 = 3 impulses 
per revolution, and an eight cylinder, 8 — 2 = 4 impulses, pro- 
viding of course, that the engine is single acting. 

Arrangement of the cylinders varies with the service for 
which the engine is intended and the perfection of balance that 
is required, the principal arrangements being the "V," the 
"upright," the opposed, the /'radial," "tandem," and "twin." 
The upright engine has the cylinders all on one side of the 
crank-shaft in a straight line, as in the four cylinder automobile 
engine. In this form, each cylinder has an individual crank 
throw the number of throws being equal to the number of 
cylinders. This engine is fairly well balanced in the four, six 
and eight cylinder types, as one-half of the connecting rods and 
throws are up, while the other half are down, but as the con- 
necting rods do not all make equal angles with the center line 
of the cylinder at the same time there is a slight unbalance in 
the four and six cylinder types. Because of the ignition se- 
quence, two cylinder vertical motors are in no better balance 
than the single cylinder type since both crank throws and con- 
necting rods are on the same side of the shaft at the same time. 
For this reason the two cylinder engine is most commonly built 
in the opposed type which gives perfect balance. 

In "V" type arrangement, one-half of the cylinders are set 
at an angle of about 90° with the rest of the cylinders, or in 
the two cylinder "V" the cylinders are set in the same plane, 
perpendicular to the shaft, at angle varying from 57^4° to 90°. 
The "V" type arrangement is adopted where light weight and 
compactness are the principal requirements, as the weight and 
length are both reduced by putting the cylinders opposite to 
one another by pairs, the "V" being practically one-half the 
length of an upright having the same number of cylinders. 
This arrangement permits the use of one-half the number of 
crank throws used in the vertical type as each crank throw 
acts for two cylinders. For the reason that both the cylinders 
of a two cylinder "V" act on a common crank throw, the two 
cylinder "V" is in no better balance than a single cylinder 
engine. 

An "opposed" type engine is in the most perfect mechanical 
balance of any engine as the crank shafts and connecting rods 
are not only on opposite sides of the crank-shaft, but make 
equal angles with the center line of the cylinders as well, at all 
points in the revolution. The explosive impulses occur at equal 



GAS, OIL AND STEAM ENGINES 



97 




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98 GAS, OIL AND STEAM ENGINES 

angles in the revolution as in the four and six cylinder vertical 
type. An opposed engine may be considered as a "V" having 
a cylinder angle of 180°. In the opposed type, one crank throw 
is provided for each cylinder, the pistons of the opposite cyl- 
inders traveling in opposite directions at the same time. 

A "radial" or "Fan" type motor, as the name would suggest 
has the cylinders arranged in one or two rows around ihe 
crank case, each cylinder being on a radial line passing through 
the center of the cylinder with one crank throw for each row. 
The Gnome engine illustrated elsewhere in the book is an ex- 
ample of this type, the seven equally spaced cylinders acting 
on a common crank throw. When more than seven cylinders 
are used on this engine, as in the fourteen cylinder engine, two 
cranks are provided, each crank serving seven cylinders. This 
arrangement cuts down the weight of a motor enormously be- 
cause of the short crank shaft and case. With the ignition 
properly timed and the cylinders correctly spaced the firing im- 
pulses occur at equal angles. 

"Tandem" cylinders are employed only on stationary engines, 
the cylinders being placed on the same center line, one in front 
of the other, and when this arrangement is adopted it is the 
usual practice to make the cylinders double acting. The two 
pistons are connected by a rod known as the "piston rod" which 
extends from the rear end of one cylinder into the front of the 
following cylinder. Tandem cylinders require too much room 
for use on automobiles or motor boats, and for this reason are 
seldom seen in this service. 

The "twin" engine is a modification of the vertical cylinder 
arrangement, both cylinders being on the same side of the 
shaft and in line with one another. It is the type most gen- 
erally used on very large stationary engines that have more 
than one cylinder, and instead of being vertical as in their 
prototype are generally laid horizontally. Since the twin en- 
gine is generally double acting, the crank throws are placed on 
opposite sides of the shaft. 

(45) Four Cylinder Vertical Auto Motor. 

A common type of four cylinder vertical motor is shown by 
Fig. 19, which is of the type commonly used on automobiles. In 
order to show the general construction of the cylinder, each 
cylinder is cut through at a different point. The cylmder at the 
extreme left is shown in elevation, or as we would see it from 
the outside. In the second cylinder from the left, the section 



GAS, OIL AND STEAM ENGINES 99 

is taken through the valve chamber, which projects from the 
side of the cylinder. A section through the center of the cyl- 
inder is shown on the third cylinder, and the fourth cylinder is 
in elevation. 

On cylinder No. 1, (left) is seen the exhaust pipe (32) and 
the inlet pipe (31) entering to valve chamber and connected 
to the exhaust valve and inlet valve respectively. The pipes 
are held in place by the clamp or "crab" {33). The exhaust 
pipe connects with the exhaust valve of each cylinder, and 
terminates at the fourth cylinder as shown by (32). Screwed 
into the top of the valve chamber on cylinder No. 1 are the 
two spark plugs (34) and the relief cock (35). 

Referring to cylinder No. 2, the inlet valve (42) is shown at 
the left of the chamber and the exhaust valve also shown by 
(42) is shown at the right. Above the valves are the spark 
plugs (34) which project into the space above the valves. Press- 
ing against the lower ends of the valve stems and holding the 
valves tight on their seats are the springs (44) which fit into the 
washers (45) fastened to the stems. The valve stems terminate 
in a nut at (48). The valve stem guides (43) form a support 
for the valves and at the same time form an air tight connec- 
tion for the stems to slide in. 

Immediately beneath the stems are the push rods (46) which 
are provided with an adjustment (48) at the upper end, and a 
roller (49) at the lower end. The rollers (49) rest directly 
on the cams mounted on the cam shaft (27), and as the irreg- 
ular cams revolve, the push rods are moved up and down which 
in turn act on the valve stems and raise the valves at the proper 
moment. The cams, raise the valves and the springs close them. 
The two cams (exhaust and inlet) appear as two rectangular 
enlargements on the shaft (27). The bearings (53), support 
the cam shaft, one being supplied for each cylinder. 

At the extreme left of the crank shaft is shown the half 
time gear (20) which meshes with the gear on the crank-shaft 
and drives the cams. Next to this gear is the large cam shaft 
bearing 26. It should be noted that the section through the 
valve chamber taken on cylinder No. 2 is at a point consider- 
ably back from the center line of the cylinders and not in the 
same plane as the section shown on cylinder No. 3, which is 
taken through the center line of the cylinders. 

In the section of cylinder No. 3, we see the water space sur- 
rounding the upper portion of the cylinder with the opening 
(37) connected to the water manifold (36), through which the 



100 GAS, OIL AND STEAM ENGINES 




Fig. 19. Cross-Section Through Typical Four Cylinder Automobile 
Engine. Courtesy of the Chicago Technical College. 



GAS, OIL AND STEAM ENGINES 101 

water leaves the cylinder and passes to the radiator. At the 
lower end of the stroke is the piston, one-half of which is 
shown in section and one-half in elevation so that internal and 
external appearance may be readily seen. The piston pin 
(60) is located approximately in the center of the piston to 
which it is secured by means of the set-screw (61). 

By means of the connecting rod (56), the motion of the 
piston is transmitted to the crank-shaft throw (54), both ends 
of which are provided with bronze bushings (59) and (58), 
fitting on the piston pin and crank-pin respectively. Between 
each crank throw are the main crank shaft bearings (55) which 
are provided with the bronze bushings (54). Below the con- 
necting rod ends is the small drip trough containing oil into 
which the pipes on the rod ends dip when passing around the 
lower end of the stroke. When the pipes enter the oil puddle 
a small amount of lubricating oil is driven into the crank-pin 
bearing because of the force of impact, this force also causing 
oil to splash about in the crank case for the lubrication of the 
main crank shaft bearings and cam shaft. In order to main- 
tain a constant level of oil in the puddle so that the bearings 
shall receive a constant supply of oil, a small overflow opening 
is placed in the center of the puddle which allows an excess of 
oil to overflow into the return oil sump below. 

This excess of oil drains by gravity back to the oil circulat- 
ing pump (73), at the right which again forces the oil to the 
various bearings. In this way, the same oil is used over and 
over again until it becomes unfit for lubricating purposes be- 
cause of dirt or decomposition. The oil pump is driven from 
the cam-shaft through the level gears (66) and the vertical 
shaft (72). To the right of the oil pump is the fly-wheel (75) 
which furnishes the power for the idle strokes of the engine. 

At the upper end of the vertical shaft that drives the oil 
pump is an extension (68) which passes through the bearing 
(70) and drives the ignition timer shown at the top of the 
housing (69). The timer controls the period of ignition in the 
cylinders in regard to the piston position so that the spark 
occurs at the end of the compression stroke. At the extreme 
left of the engine is the radiator fan (1) which is driven from 
the crank-shaft pulley (16), the belt (10), and the fan pulley 
(1122). This fan increases the amount of cold air that is drawn 
through the radiator, (mounted to the left of -the engine) and 
increases its capacity for cooling the jacket water of the en- 
gine. The water circulating pump is located on the opposite 
side of the motor. 



102 GAS, OIL AND STEAM ENGINES 




Fig. 19-a. Buda Four Cylinder Automobile Motor. Carburetor Side. 




Fig. 19-b. Buda Motor, Purnp Side, Cylinders "En Bloc. ,: 



GAS, OIL AND STEAM ENGINES 



103 



In this motor both the inlet and exhaust valves are located 
on the same side of the cylinder which arrangement classifies 
the engine as an "L" type, the extended valve pockets forming an 
"L" with the center line of the cylinder. In the motor shown 
by Figs. F-14 — F-1S, the inlet and exhaust valves are on opposite 
sides of the cylinder as shown in the cross-section, which classi- 
fies the motor as a "T" type, as the valve chambers together 
with the cylinder forms a "TV' The latter type of motor has 




Fig. F-14. Cross-Section Through Wisconsin Truck Motor. "T" Type. 

several advantages over the "L" type, but as it requires two 
cam shafts, one for the inlet and one for the exhaust valves, 
it is not adopted by the builders of the cheaper grades of 
automobiles. Since the exhaust valves are on the opposite 
side of the cylinder, in the 'T" type, the inlet air is not ex- 
panded nor the output diminished by the heat of the exhaust 
passages. The piping is less complicated which permits of a 
more effective arrangement of the carburetor and magneto. 
Since the piping in the latter type can be arranged to better 
advantage, less back pressure is the result. 



104 



GAS, OIL AND STEAM ENGINES 



As in the previous case, the valves are acted on directly by 
the cams and push rods, one cam shaft being provided on each 
side of the cylinders. In order to reduce the noise made by 
the push rods and springs, 'all of the springs are enclosed by 




Fig. F-15. Longitudinal Through Wisconsin Truck Motor. 

sheet metal housings or tubes. The circulating pump is shown 
at the left nearly on a line with the left hand cam shaft, the 
pump outlet being inclined toward the cylinder so that it 
enters the water jacket under the exhaust valves. Water 
leaves the jacket by the pipe shown on the cylinder tops. 



GAS, OIL AND STEAM ENGINES 



105 



From the longitudinal section it will be seen that the cylin- 
ders are cast in pairs, two cylinders to the pair, instead of 
singly as in the previous case. The large pipe crossing at 
about the center of the cylinders is the exhaust pipe (shown 
in front of the left pair), and the pipe shown under the 
exhaust is the water inlet pipe from the circulating pump. It 
will be seen from the longitudinal section that the main 
crank-shaft bearings are fastened to the upper half of the 
crank case, and are entirely independent of the lower half 
which acts simply as an oil shield. This construction allows 




Six Cylinder Rutenber Automobile Motor, with Cylinders Cast in Pairs. 

the oil shield (lower half) to be removed without disturbing 
the adjustment of the bearings, when it becomes necessary 
to inspect the internal mechanism. 

Large removable plates cover the top of the water jackets 
so that it is a simple matter to-clean out the water space in case 
that it becomes coated with deposits from the water. This 
is an important feature as a great many of the heating troubles 
may be overcome by having access to the interior of the water 
jacket. The water outlet pipes connect with the jacket covers. 
Both cam shafts are driven by the gears at the right which 
connect with the crank shaft pinion. Fan is belt driven from an 
extension to the cam shaft. 

All bearings are supplied with oil by a high pressure force 
feed pump, the crank pins receiving their supply through 



106 GAS, OIL AND STEAM ENGINES 

channels drilled in the crank shaft and pin, which in turn are 
connected to the oil supply of the main bearings, no dependence 
being placed on a splash system. After leaving the bearings, 
the oil drops into the crank case and drains into the sump 
shown at £he left of the longitudinal section. From the sump, 
the oil returns to the oil pump from which point it is returned 
to the circulating system under high pressure. 

(46) Stationary Four Cylinder Engine. 

An English stationary engine, the Browett-Lindly, similar 
in many respects to the automobile engines just described, is 




Fig. 21. Cross-Section Through Browett-Lindly Engine. 

shown in longitudinal and cross-section by Figs. 20 and 21. 
This is of the "L" type of valve arrangement, but instead of 
having the valves side by side as in the preceding case, the 
inlet valve is placed over the exhaust as will be seen from the 
cross-section view. 

The exhaust valve is operated directly from the cam shaft 
by the push rod as in the auto engines, but the inlet valve 
receives its motion through a long vertical rod and horizon- 
tal lever, the latter being located on the cylinder head as shown 



(J AS, OIL AND STEAM ENGINES 



107 



by the longitudinal section. A supplementary valve is mounted 
loosely on the stem of the inlet valve, and this valve is held 
against the seat of the gas inlet port by a short spring. 

A collar on the main valve spindle opens this gas valve, and, 
by adjusting the position, a certain amount of lag can be given, 




Fig. 20. .Section Through 



Browett-Lindly 
Engine. 



Four Cylinder Stationary 



so that air first enters the cylinder and then, by further travel of 
the main valve, the gas valve opens and the combined charge 
is taken in. This prevents any "back fires" as the gas and 
air are entirely separated until they enter the cylinder. 



108 



GAS, OIL AND STEAM ENGINES 



Starting is effected by means of compressed air, and is en- 
tirely automatic. No compression release is provided, as this 
is unnecessary under the system adopted. By opening tne 
main compressed air valve compressed air is admitted to two 
valve boxes placed underneath the cam shaft, and the pressure 
of air raises the valves against their levers and cams. Should 
the swell on the cam be opposite a lever as it will be in the 
correct starting position, the valve cannot close, and the com- 
pressed air then passes to the cylinder through a check valve 
on the face of the cylinder, and the engine starts. The auto- 
matic check allows the cylinders to take in a charge of mix- 




Fig. 21 -a. 



Section Through Cylinder of Fairbanks-Morse Type "R E" 
Engine, with Valves in the Head. 



ture on the second stroke and firing takes place immediately. 
When. the explgsion pressure fs greater than the air pressure 
the check remains closed and no more starting air enters the 
cylinder. 

Governing is effected by varying both the quantity and qual- 
ity of the mixture. 

The main valve, plunger, and rod springs, and all springs on 
the valves and valve motion, are arranged to be in compression. 
The exhaust valves are of cast-iron, and are fitted with renew- 
able seats in the cylinders. The admission valves are of nickel 
steel, and are arranged in boxes, which, when removed from 
the cylinders, provide the ports which give access to and space 
for the removal of the exhaust valves which are withdrawn 
vertically. 



GAS, OIL AND STEAM ENGINES 109 

Forced lubrication is fitted throughout all bearings, valves, 
plunger guides, governor, cam shaft, etc., the oil under pressure 
being supplied by two valveless pumps, either of which is suffi- 
cient to maintain the working pressure of oil. 

The normal output of the engine is 400 brake horse-power, 
with an allowable overload of 40 horse-power for y 2 hour. The 
exhaust pipe is water jacketed, each section being supplied from 
the small pump shown at the end of the cross section. 

Double ignition is provided for an emergency, by two high 
tension magnetos, each of which is connected to a separate set 
of plugs. When starting the engine, an ordinary spark coil and 
storage battery are used until the engine gets up to speed, 
when the coil is cut out and the magneto is thrown in. 

(47) The "V" Type Motor. 

An example of the "V" type motor is shown by Fig. 22, which 
is a front elevation of the Frontier aeronautic motor, a type 
that occupies a minimum of space with a minimum of weight. 

The cylinders are cast separately and are furnished either 
with iron or copper water jackets, the copper jackets being 
deposited over the cylinder barrels by an electrolytic process 




Fig. 22, End Elevation of Frontier 8 Cylinder "V" Type Motor. 



110 GAS, OIL AND STEAM ENGINES 

in much the same way as that of the celebrated French Antoin- 
ette. Bolts passing through flanges on the bottom of the cyl- 
inder fasten them to the base. A special aluminum alloy is 
used for the base which is cast in a single piece with webs to 
receive the bearings. A unit crank-case insures perfect align- 
ment, prevents a greater part of the oil leakage, and forms a 
much stronger construction than the usual split pattern. A 
chamber is provided for the cam shaft at the apex of the case 
through which issue the push-rods. Shafts and piston pins are 
hollow. All push rods are adjustable for wear and have steel 
balls running on the cams which eliminate the possibility of 
mis-timing through wear. 

Lubrication is by a bronze pump geared from the crank-shaft 
and is connected to an oil tank located in the base from which 
the oil is forced through the crank-shaft up through the hollow 
connecting rods to the piston pins, thence to the cylinder 
walls, the surplus returning to the tank in which the strainer is 
located. 

The circulating pump is driven from the cam shaft as shown 
in the cut and supplies the cylinders and radiator with water 
through the copper water manifolds which are designed to 
give an equal supply to each cylinder. Exhaust manifolds are 
of seamless steel tubing. 

The cylinders are 4^ bore x 4^g stroke, and develop 60 to 
70 horse-power at 1,100 revolutions per minute, which speed 
has been attained with an 8-foot 6-inch propeller having a pitch 
of 5 feet. Without radiator or propeller, the iron jacketed motor 
weighs 312 pounds, and copper jacketed weighs 290 pounds, 
the latter making a difference of 22 pounds in the weight. 

A high tension Bosch magneto is used which is mounted on 
a pad cast on the top of the crank-case and is driven from a 
gear meshing with the cam shaft gear. Connection is made 
from the magneto to plugs placed over the inlet valves in the 
valve caps. 

A 100 horse-power aero engine of the "V" type is shown by 
Figs. 23-24-25, which is built by the All British Engine Com- 
pany for the aeronautical branch of the English War Depart- 
ment. It has eight cylinders of 5 inch bore, by A 1 /^ inch stroke, 
and develops its rated horse-power at 1,200 revolutions per 
minute. Data from "Aero" London. 

The crankshaft, which is of three per cent nickel chrome steel, 
having an ultimate tensile strength of 157,000 lbs. per sq. in., 
is of distinctly large diameter, and is carried in plain bearings 



GAS, OIL AND STEAM ENGINES 



111 




Fig. 23. Longitudinal Section Through A. B. C. 100 Horse-Power 

"V" Motor. 



112 



GAS, OIL AND STEAM ENGINES 



lined with white metal. It is provided with four throws, each 
crank pin being arranged to take the big end bearings of two 
connecting rods from cylinders on opposite sides of the crank 
case. There is a bearing between each throw, and in order to 
reduce the overall length of the engine the cylinders are stag- 
gered on the crank case. The H section connecting rods are 
stamped out of steel having a tensile strength of 90,000 lbs. per 
sq. in., and for the purpose of lubrication a hole is drilled from 
end to end down the center of the web. As mentioned before, 




Fig. 24. Valves and Valve Motion of A. B. C. Motor. {"Aero," London.) 



the cylinders are staggered, and there is no overhanging of 
the big end bearings at the point of attachment to the con- 
necting rod. The bearings themselves are lined with white 
metal. The small end bearings are provided with phosphor 
bronze bushes, and the piston pin is of steel bored out hollow 
and hardened. 

A very interesting detail of the engine is the combination of 
the water outlet pipe from the top of the cylinder with the 
bearings for the rocking arms (which are steel stampings) 
actuating the valves. This is shown in Fig. 25. A hollow steel 
column is bolted to the top of the cylinder and protrudes from 
the water jacket, which is fastened to it with the usual shrunk 



GAS, GIL AND STEAM ENGINES 



113 



ring. To this column rs attached a hollow T shaped pipe of 
phosphor bronze, the column of the T piece forming the out- 
let for the water. On one arm of the T piece the exhaust 
rocker takes its bearing and on the other the inlet rocker. 
Each T piece arm is connect i to its fellow on the next cylin- 
der by means of rubber pip . 




Fig. 25. End Elevation of A. B. C. Motor. 

A small bracket projecting from the T piece forms a saddle 
on which the valve spring rests. This is a plain semi-elliptical 
leaf spring which works both valves. It is slotted at each end 
and slightly turned up so as to engage with a cotter pin passed 
through a slot in the end of the valve stem. 

The crank case is of rather unusual design, being absolutely 
circular in section and machined all over. It is practically a 
tube with flanged portions bolted on to form the ends. Having 
no horizontal joints, it is strong and easily kept oil tight. Three 



114 



GAS, OIL AND STEAM ENGINES 



radial arms, with slight webs and reinforced with steel colums 
down the center, support each bearing. The crank case is car- 
ried by four feet, which are arranged to accommodate three 
different widths of engine bearer. To the fore end of trie crank 
case is bolted a long conical aluminum nose carrying at its ex- 
tremity a compound push and pull ball bearing 6 in. in diametei, 
which supports an extension shaft bolted to the crankshaft by 
means of a flanged coupling. 



Wmm 


• 


^1 I/*- 

it 










Ml 


§/ §IK 



Fig. 24-a. "Sixteen". Cylinder Favata Radial Type Aero Motor, Con- 
sisting of Four Groups of Two Cylinders Per Group. Cylinders are 
of the Double Acting Type and are Stationary. 

At the outer end of this extension is a flange to which the 
propeller is bolted, but the arrangement is specially devised to 
make quick detachment possible. The boss of the propeller has 
a hollow hub and is plate bolted permanently to it by twelve 
bolts. 

The direct nose is interchangeable with a speed reduction 
gear so that the propeller can be driven at a lower speed than 
the engine. Fitting this gear nose raises the center line of the 
propeller-shaft some $% in. The 'gears are carried on sub- 



GAS, OIL AND STEAM ENGINES 115 

stantial ball bearings, plain bearings being used also in such a 
way that they take up the load if the ball bearings through 
any cause should fail. The reduction is by means of silent chains. 
The arrangement of the gear wheels is plain from the drawing, 
and it will be noticed that there is no intermediate wheel be- 
tween the crankshaft pinion and the camshaft wheel, which are 
of steel and phosphor bronze respectively. A separate gear 
wheel is provided on the camshaft for driving the magneto. 
The water and oil pumps are carried low down outside the 
crank case, and are driven by intermediate wheels at double 
the engine speed. The shafts are joined together through 
Oldham couplings, so that it is possible to remove the pumps 
separately. Both these pumps are of the gear type. 

The camshaft is made in one piece with the cams, and is 
hardened, being drilled out for lightness. It is enclosed in a 
casing of steel tube, which is practically separate from the 
crank case, being attached thereto at one end by the timing 
gear case and at the other by a saddle. The camshaft is car- 
ried in six bearings. An interesting point is the fact that the 
gear wheels are bolted to flanges on the shafts instead of be- 
ing attached by keys. Carried in the tube directly above the 
camshaft is a second shaft forming the fulcrum of the rocking 
arms for the cam rollers. A very interesting point is the pro- 
vision of an arrangement for lifting the exhaust valves. The 
little rocking arms carrying the rollers which bear upon the 
cams are provided with webs, parallel with the camshaft and 
between it and the shaft carrying the rockers is a third shaft, 
the sides of which normally just clear the webs of the rock- 
ing arms on either side. This shaft is provided with wedge 
shape pieces along it, so that by sliding it along the wedges 
lift the rocking arms clear of the cams, and thus, through the 
tappet rods and rockers, the valves themselves are opened. 

Xot the least interesting particular of this engine is the 
thorough way in which the lubrication is carried out. Four 
of the bolts which attach the caps of the main bearings are 
prolonged through the bottom of the crank case, and serve to 
carry a detachable oil sump which holds sufficient oil for a run of 
six hours. As already mentioned, the oil pump is driven at twice 
the engine speed, and maintains a pressure of something like 110 
pounds per square inch. It delivers directly into a straight steel 
tube placed along the bottom of the crank case, and from 
this tube a vertical tubular connection is taken to each of the 
caps of the main bearings. The crankshaft and crank pins are 



116 GAS, OIL AND STEAM ENGINES 




Fig. 26. Mesta Engines on Test Floor. 



GAS, OIL AND STEAM ENGINES 117 

hollow, and, as in the previous engine, in the hollow portions 
tubes of a slightly smaller diameter are placed, the tubes being 
expanded over at the ends, so that closed annular spaces are 
formed which are used as lubrication leads. The lubricating 
oil passes through the main bearings into these annular spaces 
in the shafts, from them to the annular spaces in the crank 
pins, and so to the big-end bearings. From the big-end bear- 
ings it travels up the connecting rods to the gudgeon pins. 
It is interesting to note at this point that the connecting rods 
work in slots in the crank case which just allow sufficient clear- 
ance for their travel, in order to prevent the flooding of oil 
into the cylinders. A steel-lined oil lead is taken up to the 
saddle which supports the tubular camshaft casing at the pro- 
peller end of the crank case. The bearings carrying the cam- 
shaft are cut away at their lower edges clear of the tube so 
that the oil can flow along the full length of the casing, the 
level being sufficient to allow the cams to dip. Precautions are 
taken to keep oil from flowing out of the bearings, and the 
casing over the gears is specially arranged to prevent the oil 
from flooding below. 

(48) Mesta Gas Engines. 

The Mesta four stroke cycle, double acting gas engine, built 
by the Mesta Machine Co., Pittsburgh, is an excellent example 
of American big engine practice. Mesta engines are built in 
sizes from 400 horse-power up to the largest used, and is built 
either in tandem or twin tandem units. While the engine does 
not differ widely in either principle or construction from en- 
gines of the same size it has several features worthy of note 
that are not found on other engines. 

Up to the medium sizes, the cylinders are cast in one piece, 
the largest cylinders being made in two parts of cast steel with 
air furnace iron bushings. The central part of the cylinder is 
open as will be seen from the cuts, and is covered with a 
cast iron split band bolted at the center line. The valve cham- 
bers are located directly opposite one another on a vertical 
center line, the inlet valve being at the top and the exhaust 
valve at the bottom. This arrangement gives a better dis- 
tribution of the mixture, increases the output with given size 
of cylinder and equalizes the stresses occasioned by the ex- 
plosions. As the engine is double acting in all cases there is 
one inlet and one exhaust at each end of the cylinder. 

Both the inlet valve and the corresponding exhaust valve on 



118 



GAS, OIL AND STEAM ENGINES 



each end of the cylinder are operated by a single eccentric on 
the horizontal lay-shaft shown running below and parallel to 
the cylinders. The regulating valves which are controlled by 
the action of the governor are perfectly balanced against the 
pressure in the cylinder which results in a very small resist- 
ance to the governor action, therefore no oil relay nor similar 
complications are required. Any of these valves are easily re- 
moved for clearing, a point of great importance when running 
on a gas that is laden with tar or other impurities. 




Fig. 27. End View of Mesta Engine. 

The chrome-vanadium piston rod carries the pistons float- 
ing free from the cylinder walls reducing the wear on the bore, 
while the piston rings maintain a gas tight contact with the 
cylinder walls. Each piston rod is made in two halves, the 
joint between the sections being made between the cylinders at 
which point the rods are supported by an intermediate cross- 
head and guide. Both parts of the rod are interchangeable. 
The pistons are made in one casting. As will be seen from 



GAS, OIL AND STEAM ENGINES 119 

the accompanying cuts the front end of the piston rod is car- 
ried by a cross-head which relieves the pressure on the piston 
and packing glands. 

Speed regulation is performed by the governor by control- 
ling both the quantity and the quality of the mixture. Inde- 
pendent valves in the gas and air passages are actuated by the 
governor according to changes in the load. This method of 
control combines all of the good features of quantity and 
quality regulation. 

Make and break ignition is used, with the igniter trip gear 
so designed as to allow all of the igniters to be timed from 
one lever, or adjusted independently as the case may require. 
Each combustion chamber is supplied with two igniters, one 
at the top and on at the bottom, which insures regular and 
rapid combustion and therefore gives a maximum of efficiency 
and reliability. 

Compressed air is introduced into the cylinders for starting 
at a period corresponding to the power stroke in normal opera- 
tion. This is accomplished by cam operated poppet valves 
located in the air main and check valves in the cylinders. By 
this system the engine can be started and put on full load in 
less than one minute. 

(49) Knight Sliding Sleeve Motor. 

The Knight motor was the first four stroke cycle automobile 
motor to employ an annular slide valve in place of the usual 
poppet valve. Its success has led to the development of sev- 
eral other motors of a similar type which follow the construc- 
tion of the original engine more or less closely. Being free 
from the slap bang of eight to twelve cam actuated poppet 
valves which hammer on their seats at the rate of a thousand 
blows per minute, the Knight motor is free from noise and 
vibration. Instead of the jumping of a number of small parts, 
there is only the slow sliding of the sleeves over well lubricated 
surfaces. They make no noise because they strike nothing and 
can cause no vibration because they are a perfect sliding fit 
in their respective cylinders. 

Besides insuring noiseless operation, the valves increase the 
output, efficiency and flexibility of the motor for they are posi- 
tively driven and are not affected in timing by fluctuations in 
the speed. The wear of the reciprocating increases the effi- 
ciency of the sleeve instead of destroying it. With poppet 
valves at high speeds, the valves do not seat properly in rela- 



120 



GAS, OIL AND STEAM ENGINES 



tion to the crank position owing to the inertia of the valves 
and to the gradual weakening of the valve springs which delays 
the closing of the valves. Carbon also gets on the seats of 
the poppet valves and prevents proper closure. These faults 
cannot exist with sliding sleeves when they are once set right 




Fig. 28. Section Through Knight Motor Showing the Sleeves, Eccen- 
trics, and Automatic Adjustment for Lubrication. Inlet is at the 
Right, Exhaust at the Left. 

as they are positively driven through a crank and connecting 
rod. 

At high engine speeds the velocity of the exhaust and inlet 
gases is very high in the poppet valve type due to the many 
restrictions and turns in the passages which causes back pres- 



GAS, OIL AND STEAM ENGINES 



121 



sure and a considerable loss of power. With the sliding sleeve 
type an ideal form of combustion chamber is possible and the 
passages to and from the chamber are short and direct. Very 
large port areas with a low gas velocity are also possible. The 
sleeves are more effectively cooled than the poppet type, being 
in direct contact with the water cooled walls for their entire 




INLET OPENS 





INLET CLOSES 



INNER SLEEVE UE 
OUTER SLEEVE \S 
MOVING DOWN 



BOTH SLEEVES 
ARE MOVING UP 
IN REGISTER. 



BOTH SLEEVES 
ARE MOVING UF^ 
INNER CLOSES. 



—28— 
Figs. 28-29-30. 



-29— 



—SO— 



Showing Sleeve Positions on the Inlet Stroke. 
Motor.) 



(Knight 



length. Because of the large port areas, the cylinders receive 
a full charge of mixture, and as a result the engine accelerates 
and gets under way with remarkable ease. 

The arrangement of the slide valves, or sleeves, is shown 
by Fig. 28, which also gives an idea of the cylinder form, and 



122 



GAS, OIL AND STEAM ENGINES 



the location of the piston. Fitting the engine cylinder closely, 
one within the other, are the two sliding valve sleeves, and 
within the inner sleeve slides the power piston. 

Each sleeve has two slots cut in it, one on each side, which 
form an outlet and inlet for the exhaust and inlet gases respect- 
ively. When the slots on the intake side of both the outer and 





OPEN 




iA 






7 



EXHAUST CLOSES 



BOTH ARE MOV- 

we down, both 

SLOTS ENTERING 



BOTH ARE MOV- 
ING DOWN IN 

RES\8TER. 



INNER SLEEVE U P. 
OUTER SLEEVE 13 
MOVING DOWN. 



--31— —32— — 33— 

Figs. 31-32-33. Showing Sleeve Positions on the Exhaust Stroke. 



the inner sleeves register, or come opposite to one another, 
and also opposite to the intake pipe, a charge of gas is drawn 
into the cylinder. After the explosion has taken place, the 
sliding motion of the sleeves brings the other two openings, on 
the exhaust side, opposite to one another, and opposite the 



GAS, OIL AND STEAM ENGINES 123 

exhaust pipe, which allows the burnt gas to escape to the at- 
mosphere through the exhaust manifold. 

The sleeves are driven from cranks on the half-time shaft 
shown at the side of each cut, through the small connecting 
rods, which gives them a reciprocating motion. Like the cam 
shaft on a poppet valve motor, the lay shaft runs at half the 
crank shaft 'speed, since the engine is of the four-stroke cycle 
type. The lower ends of the sleeves, to which the connecting 
rods are fastened, are made thicker than the portion within 
the cylinder, and are heavily ribbed for strength in the over- 
hang. 

The sleeves are of the same composition of cast iron as the 
cylinder and are provided with oil grooves cut in their outer 
surfaces for gas packing, and the distribution of oil. Leakage 
between the inner sleeve, and the cylinder head is prevented 
by a packing ring, or "junk" ring that is fastened to the bot- 
tom of the inwardly projecting cylinder head. The junk ring 
not only prevents the leakage of gas during the explosion, but 
it also serves another purpose. 

The exhaust ports or slots in the inner sleeve are above the 
junk ring during the explosion, in which position they are pro- 
tected from contact with the burning gas. The life of valves 
is greatly increased by this protection. It will be noted that 
the entire surface of the sleeves is in contact with water jacketed 
surfaces, making perfect lubrication and smooth working pos- 
sible. The two spark plugs for the dual ignition system are 
shown in the depressed cylinder head. 

Complete water jacketing encircles the cylinders, cylinder 
heads, the circulation area enclosing the plugs and the gas 
passages so that a uniform heat is maintained the entire length 
of the piston travel. * 

The half-time shaft, the magneto, and the water pump are 
driven by a silent chain from the crank case; this drive being 
found superior to the gears commonly used for this class of 
work. The cranks on the half-time shaft are made in one in- 
tegral piece with the shaft. 

Although the piston on the Stoddard-Dayton Knight motor 
has a stroke of 5y 2 inches, it is scarcely as much as this con- 
sidered as friction producing travel, because the inner sleeve in 
which it rests moves down in the same direction 1% inches. 

This distribution of the working stroke to two surfaces 
reduces the wear on the side of the sleeve caused by the angu- 
larity or thrust of the main connecting rod. On the compres- 



124 GAS, OIL AND STEAM ENGINES 

sion stroke, both outer and inner sleeves go up in the same 
direction as the piston, the inner sleeve moving the faster. On 
the exhaust stroke and suction stroke the sleeves move in a 
direction opposite to the direction of the piston, but on these 
strokes there is very little work performed by the piston and 
consequently little thrust is produced on the sleeves and walls 
of the cylinder. 

It is a valuable feature to have the sleeves descend with the 
piston on the working stroke because this is the stroke in 
which the piston has the greatest amount of side thrust. 

The up and down movement of the sleeves is very little com- 
pared with that of the piston. A stroke of Sy 2 inches gives a 
piston speed of 916 feet per minute at a speed of 1,000 revolu- 
tions per minute. The stroke of the sleeves is lj£ inches and 
its speed is but 93.7 feet per minute, or a little more than 
one-tenth that of the piston. This fact makes the problem of 
lubrication a feasible one, the slow-movement of the sleeves 
distributing the oil thoroughly between them as well as be- 
tween the outer sleeves and the cylinder walls. 

The action of the valves, and their position at different points 
in the cycle, is shown in diagrammatic form by Figs. 28-29-30- 
31-32-33, the particular event to which each diagram refers 
being marked at the foot of the cuts. The direction of the 
sleeve movement is indicated by the arrows at the bottom 
of the sleeves. Particular attention should be paid to the posi- 
tion of the slots in the sleeves. 

The first three diagrams show the position of the inlet shots 
that govern the admission of the combustible gas from the 
carburetor. Fig. 28 shows the slots coming together to form 
an opening in the inlet port as the lower edge of the outer 
sleeve separates from the upper edge of the inner sleeve. The 
outer sleeve is now moving rapidly downward while the inner 
sleeve is slowly rising, and as their motion is opposite the 
opening is quickly formed. Fig. 29 shows the full opening 
with the slots in register. 

When closing (Fig. 30) the outer sleeve is nearly stationary 
while the inner sleeve is rising rapidly. When the inner sleeve 
port is covered by the lower edge of the junk ring, the valve 
opening is closed, the slot in the outer sleeve remaining oppo- 
site the inlet opening. 

The exhaust port opens (Fig. 31) when the lower edge of 
the slot in the inner sleeve leaves the junk ring in the cyl- 
inder head, the sleeve moving rapidly downward at the mo- 



GAS, OIL AND STEAM ENGINES 125 

ment of opening. To obtain a rapid opening of the exhaust, 
the ports are arranged so that the inner sleeve is just about 
to reach its maximum speed at the time of opening. 

The outer sleeve closes the port (Fig. 33), closure starting 
when the upper edge of the outer sleeve coincides with the 
lower edge of the ^cylinder wall port. At this time the outer 
sleeve is traveling downward at maximum speed, so that the 
closing of the exhaust is as rapid as the opening. 

The lubrication of the Knight motor is accomplished by what 
is known as the movable dam system, which overcomes the 
tendency of the motor to over-lubricate. A movable trough is 
placed under each connecting rod, in the crank case, that is 
connected to the carburetor throttle lever in such a way that 
the opening and closing of the throttle raises and lowers the 
troughs. 

When the throttle is opened, raising the troughs, the points 
on the ends of the connecting rods dip deeper into the oil which 
creates a splashing of oil on the lower ends of the sliding 
sleeves. In this way the oil is fed to the engine in direct pro- 
portion to the load and the heat produced in the cylinder. When 
the motor is throttled down, the points barely dip into the oil. 

An excess of oil is fed to the troughs by an oil pump, which 
keeps them constantly overflowing. The overflow is caught in 
the pumps located in the crank case, and returned .to the circu- 
lation so that it is used over and over again. 

Claims of great efficiency are made for this system, there hav- 
ing been many tests made showing 750 miles per gallon of oil, 
while even as high as 1,200 miles per gallon has been made un- 
der favorable conditions. 

The oil pump is contained in the crank case, and is of the 
gear type, insuring positive action. The pump also acts as a 
distributer, a slot being cut in one of the gears which register 
successively with each of the six oil leads. In this way it is 
possible to obtain the full pump pressure in each lead should 
they become obstructed in any way. 

In the upper half of the crank case are cored passageways 
through which the air passes before reaching the carburetor. 
These passages not only eliminate *he rushing sound of the 
intake air, but also form an efficient method of warming the 
air supplied to the carburetor and cooling the crank-case. It 
is possible to furnish warm air after the engine has been idle 
for several hours, as the oil in the crank case remains warm 
longer than any other part of the engine. 



126 



GAS, OIL AND STEAM ENGINES 



(50) Reeves Slide Sleeve Valve. 

A simple and compact form of slide sleeve valve gear has 
been developed in England that is of more than passing interest. 
It permits of a maximum area for both the inlet and exhaust 
gases which of course keeps the velocity and back pressure at 
a minimum for a given valve lift. The small lift also insures 
noiseless operation and a small amount of wear. The sleeve 




Fig. 34. Reeves Slide Valve Gear. 

is balanced at the end of the working stroke. The combustion 
chamber is nearly hemispherical in shape which reduces the 
heat loss to the walls. 

Referring to the section of the end of cylinder given in the 
diagram, (34) A is an open-ended water-jacketed cylinder in 
which the piston B works. At the upper end of the cylinder is 
attached a ring C forming an extension of the stationary cylin- 
drical head D carrying the sparking plug. At the lower end 
of the head D is provided a seating E for the sliding cylindrical 



GAS, OIL AND STEAM ENGINES 127 

inlet valve F, which takes its bearing around the circular head. 
This inlet valve is provided with expanding rings G to keep 
it gas-tight. Surrounding the inlet valve F is a second cylindri- 
cal exhaust valve H, which is provided with an angular seating 
at J. The outer circumference of the cylindrical exhaust valve 
H bears against the walls of the cylinder. 

Cast in the cylinder is an annular space K communicating 
with a passage L for the admission of the inlet gases. These 
pass through suitable ports cut in the sides of the exhaust 
valve H and the inlet valve F, so that they are free to pass 
through the space made when the inlet valve F is lowered from 
its seat. A similar type of annular space M is cast in the 
cylinder in connection with an opening O for the passage of 
the exhaust gas when the cylindrical valve H is raised from its 
seating at J. 

The cylinder head is not water jacketed as the builder states 
that the continual passage of the intake gases keeps it reason- 
ably cool. The exhaust passages are thoroughly water cooled. 

(51) Argyll Single Sleeve Motor. 

The Argyll sliding sleeve automobile motor is unique in the 
fact that only one sleeve is used to control both the inlet and 
exhaust gases instead of the two sleeves commonly used on 
the Knight motor. This sleeve, instead of having either a 
purely vertical or horizontal motion, has a peculiar combina- 
tion of the two, that is to say, it moves a certain amount in 
rotation within the cylinder, and an equal amount vertically, 
the combined motion constituting an ellipse. The external ap- 
pearance of the engine is shown by Fig. 35, which will give an 
idea of the general arrangement of the cylinders, ports and 
piping. 

In Fig. 36, is shown the successive movements and events 
determined by the sleeve, and the method of opening and clos- 
ing the inlet and exhaust ports by the elliptical movement of 
the sleeve. The shaded ports are one of the inlet and one 
of the outlet ports, respectively, which are cast in the cylinder 
wall, and are afterwards machined true. The dotted port, which 
changes its position in each diagram, is one of the ports in the 
moving sleeve, its position in each of the figures is marked 
by the event that is occurring in the cylinder at that time. 

In diagram 1, the shaded port to the right is the exhaust 
port, and the shaded port to the left, the inlet, this relative 
arrangement being true, of course, in each of the succeeding 



128 



GAS, OIL AND STEAM ENGINES 



diagrams. It will be noted, that in the position shown, in the 
exhaust stroke (beginning of stroke), the sleeve port has just 
started on its downward stroke, moving also a trifle to the 
right as it progresses. Its progress to the right may be more 
clearly seen by consulting diagram 2, for the movement. 

By consulting the other five figures it will be seen that the 
dotted port, in its relation to the shaded ports, first moves out 
to the right, and then reverses, moving to the left, and this 
combined wih the up and down movement constitutes an ellip- 




Fig. 35. Elevation of Argyll Single Sleeve Motor from The Motor, 

London. 



tical path. In diagram 6 the exhaust is closed, and the inlet 
port has just begun to open, the dotted port now starting to 
move out to the left, and to rise. 

In diagram 10, the inlet is nearly closed, the sleeve port pass- 
ing away from the cylinder ports to the water jacketed portion 
of the cylinder above. 

This series of diagrams shows the operation of the dupli- 
cated port of the sleeve (which port is the one shown dotted) 
in relation with one of the inlet ports and one of the exhaust 
ports in the cylinder wall, the latter ports being marked re- 
spectively I and E. The elliptical movement referred to in the 
text can be traced by following the different positions of the 



GAS, OIL AND STEAM ENGINES 



129 



dotted port in the sleeve. In the top row of diagrams it is 
seen to come downwards and also to move over to the left, 
whilst in the lower set it rises — bearing still to the left — until, 
after Fig. 10, it goes higher up for the compression and ex- 
plosion strokes, during which it bears over to the right and 
comes down again ready to commence once more the cycle, 
as in Fig. 1. The other ports in the cylinder wall are the same 




CXHAU67 eeClMS TO Cv.O*>£ 



51 



F,«. * 



-r 



\oecmsTo close 



iP„ 



Cxn.NCARur ococsO 






f.c.5 




^'IWCEX MKAIU.V CUDSEO 




«'i TT7 - «— — ■- 




>WF-^L 


t 



f.C.3:, FlClO 

Fig. 36. Valve Motion Diagram of Argyll Motor Showing the Valve 
Positions at Different Parts of the Working Stroke. 



as those shown, and the other ports in the sleeve are* akin in 
shape to half of the dotted port, but they are without the little 
tongue cut in the base of this double purpose port. This little 
tongue in the duplicated port is designed to give as much lead 
to the exhaust opening as possible, without interfering with the 
correct timing of the inlet port. The way in which it just misses 
interfering with the closing of the inlet port is seen in Fig. 10. 
We are indebted to "The Motor" for these cuts. 



130 



GAS, OIL AND STEAM ENGINES 



(53) Sturtevant Aeronautical Motor. 

The cylinders of the Sturtevant aeronautical motor are of 
the "L" type and are cast separately with the cylinder barrel 
and water jacket in one integral casting. A special iron is 
used for these castings that has an ultimate tensile strength of 
40,000 pounds per square inch. The valves which are easily 
accessible through valve covers, are operated directly from the 
cam shaft without valve rockers. A hollow cam shaft is used 
with integral cams to insure a maximum of strength with a 
minimum of weight, and bearings are placed between each set 




Fig. 41. Six Cylinder Sturtevant Aero Motor. 

of cams. A bronze gear fitted on the cam shaft meshes with 
a gear on the crank shaft without intermediate idlers. 

Like the cam shaft, the crank is bored out from end to end 
with a propeller flange applied on a taper at one end of the 
shaft. A bearing is provided between each throw with an addi- 
tional thrust bearing at the forward end of the shaft which 
may be arranged to take either the thrust or the pull of the pro- 
peller. Lubricating oil is applied to all the bearings under a 
pressure of twenty pounds per square inch, this pressure being 
maintained by a gear pump attached directly to the end of the 
cam shaft. The oil is transferred from the pump to the bearings 
through passages cast in the base, no piping being used. Oil 
enters the hollow crank shaft at the main bearings and is con- 



GAS, OIL AND STEAM ENGINES 



131 



ducted through the arms to the connecting rod bearings. The 
oil flying from the crank shaft falls into the oil sump at the 
bottom of the case where it is cooled before being used again. 
A second gear pump in tandem with the first takes the oil from 
the sump and forces it through a filter into the tank. 



It 



w 



mi 



3 
03 





This system enables the use of a more efficient filter than 
with the suction type and eliminates any danger of its becoming 
clogged and stopping the oil supply, since, in the event of such 
an occurrence the pump would furnish sufficient pressure to 



132 GAS, OIL AND STEAM ENGINES 

burst the filter. However, the filter is particularly accessible 
and may be instantly removed for cleaning without disturbing 
the oil. The tank regularly fitted to the motor holds sufficient 
oil for three hours' use. If the engine is required to operate for 
a longer time without opportunity for replenishing the oil sup- 
ply, a larger tank can be used. As no oil is allowed to accu- 
mulate in the base with this system of lubrication, the motor 
can be operated continuously at an angle. 

Water circulation is maintained by a centrifugal pump of 
large capacity, the impeller of which is mounted directly on an 
extension of the crank shaft, eliminating the usual bearings and 
its grease cup. 

The ignition is provided by a high-tension Mea magneto, its 
special construction permitting the motor to be started under 
a retarded spark avoiding the danger of back kick from the 
propeller. 

The cylinder and all exposed parts are rendered absolutely 
weather-proof by means of a heavy coat of nickel plating. 

(54) The Rotating Cylinder Motor. 

While it is the common belief that the rotary cylinder gaso- 
line motor is of French origin it may safely be said that this 
type of motor was in actual use in America for several years 
before it even reached the experimental stage in Europe. The 
Adams-Farwell Company of Dubuque, Iowa, were driving auto- 
mobiles successfully with a rotary cylinder motor before Or- 
ville Wright flew at Fort Meyer, Va. Although the original 
Farwell motor more than proved its right to existence by faith- 
ful service under the most exacting conditions, the motor never 
received the consideration that it deserved, probably because 
of its great divergence from what is known as "accepted prac- 
tice. ,, 

In Europe no such prejudice existed, and consequently the 
type made rapid strides, although, to the writer's belief, the 
European model is inferior in many ways to the original Ameri- 
can type. The fact that this type of motor holds practically 
all of the world's aviation records speaks for its practicability 
in spite of its unusual construction. 

With the rotary motor, the cylinders and crank case revolve 
about a stationary crank shaft, the latter part not only serv- 
ing as a point of reaction of the cylinders but as a support and 
intake pipe as well. Since the crank throw remains stationary, 
the cylinders and pistons revolve about two different centers, 



GAS, OIL AND STEAM ENGINES 133 

the cylinders revolving about the crank case and the pistons 
and connecting rods about the crank pin. Since the pistons, 
cylinders, and connecting rods must necessarily revolve to- 
gether, as one unit, there is absolutely no reciprocating mo- 
tion in regard to the crank shaft except for a very slight move- 
ment due to the difference in angularity of the connecting rods. 
The motion of all the parts is strictly rotary in every sense, ex- 
cept for the relation of the pistons to the cylinders, and the 
motion is as continuous as in a turbine. This insures freedom 
from vibration. As the cylinders and crank case have consider- 
able inertia there is no need of the added weight of a fly-wheel. 
The movement of the piston in the cylinder bore is brought 
about by the difference in the centers about which these parts 
revolve. This gives cylinder displacement without the reversal 
of stresses or shock or jar. 

Because of the revolving cylinders, the mixture is supplied 
to the crank case through a hollow shaft, the gas being drawn 
into the cylinder on the suction stroke through an inlet valve 
placed in the head of the piston. As a rule, the exhaust is direct 
to the air through the exhaust valves and without manifolds or 
mufflers. The motion of the cylinders through the air multiplies 
the efficiency of the radiating Fins. 

(55) The Gyro Rotary Motor. 

In the Gyro motor, made by the Gyro Motor Company of 
Washington, D. C., are embodied all of the principles of the 
typical revolving motor, but with extensive improvements in 
the design and in the details. It weighs 3*4 pounds per horse- 
power, complete. This light weight is due to the design of the 
motor and to the use of alloy steels, and is attained without 
sacrificing strength or durability. 

Each cylinder is machined out of a heavy 3 J /2 per cent tubular 
nickle steel forging that weighs nearly 40 pounds. After the metal 
is removed and the cylinder worked down to size, the shell weighs 
but 6]/ 2 pounds. The radiating ribs on the outside of the cyl- 
inder are machined out of the solid bar, and are arranged in 
helicoid or screw-like formation around the C3'linder barrel. 
This adds to the strength of the cylinder and also aids in the 
circulation of the air. The comparative thickness of the cyl- 
inder wall may be seen from Fig. 44. The stiffening effect of 
the radiating ribs will also be noted. The crank case to which 
the cylinders are fastened is of vanadium steel, and is divided 
into two parts. In addition to supporting the cylinders, the 



134 GAS, OIL, AND STEAM ENGINES 




Fig. 45. Section Through Rotary Gyro Motor. 



GAS, OIL AND STEAM ENGINES 135 

crank case also serves as a mixing chamber for the gasoline 
and air. By removing the bolts seen between each cylinder, 
the entire working mechanism can be laid bare for inspection. 
The exterior of the case carries the exhaust valve mechanism 
and the ignition distributer. The crank shaft is a nickel steel 
forging with an elastic limit of 110,000 pounds. It is bored 
hollow throughout its length and serves as an intake mani- 
fold by conveying the mixture from the carbureter, attached 
to its outer end, to the crank case. 

The intake valves in the heads of the piston are mechanically 
operated by a specially patented movement which consists of 
two parts, a counter-balancing member, and an operating mem- 
ber. The counter balance balances the valve against the dis- 
turbing influence of the centrifugal force, while the operating 
member, which is fastened to the connecting rod, controls the 
opening or closing of the valve by the angular position of the 
connecting rod. This valve action insures a full opening of 
the valve and a full charge during practically all of the suction 
stroke. 

There are two separate paths provided for the exhaust gases, 
one being through the auxiliary exhaust ports at the end of the 
stroke, and the other path through the exhaust valve located in 
the cylinder head. The auxiliary ports may be seen in the cross- 
section directly below the piston head in cylinders 4 and 5. The 
auxiliary ports are uncovered by the piston at the inner end 
of the working stroke, and it is at this point that the greater 
percentage of the exhaust leaves the cylinder. These ports or 
holes are formed on a projecting annular ring in which enough 
material is provided to make up for the strength lost by boring 
the ports. As these ports are, in the majority of cases, bored 
at an acute angle with the center line of the cylinder, it is im- 
possible for the cylinder oil to escape. 

All exhaust valves are operated by levers and push rods con- 
nected to a cam mechanism on the outside of the crank case. 
A single cam ring operates all of the valves except where a 
step-by-step compression is desired. The exhaust mechanism 
is provided with a simple device by which the closing of the 
exhaust valve may be delayed through any portion of the ex- 
haust stroke, thus reducing the compression and adding to the 
facility of cranking. The motor is started with the compression 
entirely released in which condition it can be spun about its 
shaft with ease. 

After giving the motor its initial spin, the compression and 



136 GAS, OIL AND STEAM ENGINES 

spark are thrown in and the engine begins its normal opera- 
tion. The compression release lever may be used for starting 
or slow running and in cutting off the power regardless of the 
ignition advance or retard. 

One connecting rod, called the "master" rod, is an integral 
part of the spider that contains the ball bearings of the crank 
pin, thus controlling the angular relation between the connect- 
ing rods and cylinders. The remaining six rods are, of course, 
articulated on the spider by pins so that the rods may move 
in regard to the spider when in different parts of the stroke. 
The shell of the pistons is of a fine grade of iron, very thin and 
elastic, so that it may conform readily to the outline of the cyl- 
inder bore. The head of the piston consists principally of the 
intake valve cage, the cage carrying the piston pin as well as 
the valve. 

Oil is supplied by a positive pump that measures the lubri- 
cant in exact proportion to the load on the engine. Both the 
oil and the gasoline mixture enter the crank case through the 
hollow crank shaft and mingle in the form of a vapor. This 
oil mist reaches every moving part and results in perfect lubri- 
cation. The pistons are provided with oil shields which carry 
the oil directly to the cylinder walls and prevent the loss of 
oil through the exhaust valve. 

Ignition is performed by a high tension magneto through a 
distributer which directs the current to the proper cylinder. 
As in all rotary, engines, the Gyro has an uneven number of 
cylinders (3, 5, and 7) in order that the cylinders receive firing 
impulses through equal angles of rotation. An even distribu- 
tion of firing is impossible with an even number of cylinders, 
as two adjacent cylinders out of six alternately fire together 
and then 180° apart. This produces a very jerky turning move- 
ment, and is productive of much vibration. In the seven cyl- 
inder motor the magneto is driven by gears having a ratio of 
4 to 7, and the high tension current is distributed to the cyl- 
inders by 7 brushes, the leads from the brushes being taken 
direct to the spark plugs. 

(56) Gnome Rotary Motor. 

The Gnome was the first rotary aviation motor built in 
Europe and is still one of the most capable flight motors abroad 
as its many victories and records prove. It is built in four 
sizes, 50, 70, 100, and 140 horse-power, the 50 and 70 horse- 
power motors having 7 cylinders, and the 100 and 140 horse- 



GAS, OIL AND STEAM ENGINES 



137 



power, having 14 cylinders, which consist of two rows of 7 
cylinders per row. The cylinders of all sizes rotate about a 
stationary crank shaft while the pistons rotate in a circle, the 
center of which is the crank pin. Vibration is practically elim- 
inated at high speed as the oistons do not reciprocate in the 
ordinary sense of the word, but simply revolve in a circle, the 
reciprocating relation between the cylinders and pistons being 
obtained by the difference in the centers of the two revolving 




Fig. 



50. Cross- Section Through the Seven Cylinder Rotary Gnome 
Motor, Showing the Crank Shaft Arrangement and Valves. 



systems. The cooling effect of the radiating ribs is greatly 
increased by the air circulation set up by the rotation of the 
cylinders. This method of cooling introduces a great loss of 
power due to the blower action of the cooling ribs, this loss 
often amounting to 15 per cent of the output of the engine. 

The crank shaft is stationary and acts as a support for the 
engine, one end being fastened into a supporting spider which 
forms a part of the aeroplane frame. The crank shaft is hollow 
and also serves to conduct the mixture from the carburetor 



138 



GAS, OIL AND STEAM ENGINES 



fastened at its outer end to the crank-case of the motor. Only- 
one crank throw is provided on the seven cylinder engine as 
the cylinders are all arranged in one plane which passes through 
the center of the crank throw. In the fourteen cylinder engine 
where the cylinders are in two rows, there are two crank throws, 
one for each row of cylinders. 

The seven cylinders are arranged radially, as will be seen 
in Fig. 50, each being spaced at an equal distance from the 
crank shaft and at equal angles with one another, the arrange- 
ment in general being similar to that of the "Gyro" motor 
shown in the preceding section. All cylinders are turned 




Fig. 51. Firing Diagram of Seven Cylinder Rotary Motor. On Starting 
at Cylinder No._ 1, and Following the Zig-Zag Line in the Direction 
of the Arrows, it Will be Seen that Ignition Occurs at Every other 
Cylinder at even Intervals Through Two Revolutions, Ending at 
Cylinder No. 1. 



out of solid forged steel bars, the cylinder walls being only 
1.2 millimeters thick after the machining operation. This 
results in the strongest and lightest cylinder possible to build, 
as all superfluous material is removed and the chances of 
defects in the material are reduced to a minimum as the char- 
acter of the metal is revealed by the extended machining opera- 
tions. 

As the motor operates on the four stroke cycle system, an 
odd number of cylinders is chosen in order that the firing may 
be carried out through equal angles in the revolution to 
obtain a uniform turning movement. Since a four stroke motor 
must complete two revolutions before all of the cylinders have 



GAS, OIL AND STEAM ENGINES 



139 



fired, or completed their routine of events, it is evident that 
the number of cylinders must be odd in order to bring the 
last cylinder into firing position in the last revolution. When 
seven cylinders are used, the cylinder are fired alternately as 
they pass a given fixed point, that is, one cylinder is fired, the 
next skipped, the third fired, and the fourth skipped, and so 
on around the circle, so that the firing order in terms of the 
cylinder numbers is 1, 3, 5, 7, 2, 4, 6. The cylinders fired in 
the first revolution in order are 1, 3, 5, 7, and in the second 
revolution, 7, 2, 4, 6, the cylinder 7 being common to both 
revolutions. The cylinders are numbered according to their 




Fig. 52. Firing Diagram of Six Cylinder Rotary Motor. On Following 
the Zig-Zag Line it Will be Seen that All of the Cylinders Are Not 
Fired at Equal Intervals. In Some Cases Two Adjacent Cylinders 
Fire in Sequence, and in Others Two or Three Spaces are Jumped. 



position on the engine, and NOT according to the firing se- 
quence. See Fig. 51. 

With a six cylinder engine it is possible to fire the cylinders 
in two ways, the first being in direct rotation; 1, 2, 3, 4, 5, 6 
thus obtaining, six impulses in the first revolution, and none 
in the second. The second method is to fire them alternately, 
1, 3, 5, 2, 4, 6, in which case the engine will have turned through 
equal angles between impulses 1 and 3, and 3 and 5, but through 
a greater angle between 5 and 2, and even again between 2 
and 4, and 4 and 6. See Fig, 52. 

Mixture is drawn into the cylinder by the suction of the 
piston through an inlet valve in the piston head, in practically 



140 



GAS, OIL AND STEAM ENGINES 



the same way as in the "Gyro" motor, but unlike the latter 
motor, the valve is lifted by the suction (automatic valve) and 
not by the mechanical actuation of the connecting rod. The 
inlet valve is balanced against the effects of centrifugal force 
by a small counter-weight in the piston head, and the valve is 
held normally on its seat by a flat spring acting on the valve 
stem. The gases are brought into the crank case from the 




Fig. 53. Longitudinal Section Through Gnome Rotary Motor. 

carburetor through the hollow crank-shaft as described else- 
where. See Fig. 53. 

All exhaust valves are located in the cylinder head and are 
actuated by long push rods that are moved by individual cams 
in an extension of the crank case. The exhaust valves are 
counter-balanced against centrifugal force and are retained on 
their seats by a flat spring. The counter weights do not entirely 
overcome the effects of the centrifugal force but allow a slight 
excess to exist which will permit the engine to run with a 
broken spring. All of the exhaust gases escape directly to 
the atmosphere without piping or mufflers. 



GAS, OIL AND STEAM ENGINES 



141 



Owing to the fact that the advancing or leading face of the 
cylinder is cooler than the trailing face, the cylinder bore is 
thrown out of line by the difference in expansion between the 
two sides. Because of this distortion of the bore, a special 
form of piston ring is used, which, by its flexibility, adapts it- 
self to variations in the bore. These rings are of brass and are 
shaped like the pump leathers of a water pump so that the pres- 
sure of the explosion acting on the inside of the ring tends 




Fig. 54. Gnome Motor on Testing Stand. From Scientific American. 

to force the thin shell against the cylinder. In spitje of this 
precaution, the compression pressure is very low at the best, 
in the most of cases not over 45 pounds per square inch. The 
exhaust valve screws into the end of the cylinder and may be 
removed, complete with its seat, for the frequent regrinding 
necessary to efficient operation. After the cylinders are ground 
with the greatest care and accuracy, the finishing is carried 
still further by wearing-in the cylinder with an actual piston 
carrying an "obturateur" or piston ring. 

The bushing into which the spark plug screws is not integral 
with the cylinder as in a cast construction, but is welded into 



142 



GAS, OIL AND STEAM ENGINES 



the side of the cylinder head by means of the autogenous proc- 
ess. It is also evident that this construction enables the inlet 
valves to be easily removed, since these screw into the piston 
head. Both inlet and exhaust valves in the Gnome engine are 
removed with the greatest ease, special socket wrenches being 
supplied for the purpose. The castor oil, which is used as a 
lubricant, and the gasoline, are fed by a positive acting piston 
pump to the hollow crank shaft. The lubricant and fuel then 




Fig. 55. Gnome Motor Running On Test Stand. From Scientific 

American. 



pass through the automatic inlet valve in the head of the 
cylinder. 

The spark produced by the high tension magneto is led 
to the proper cylinder through a brush that presses on a 
revolving ring of insulating material in which is imbedded 7 
metallic segments, one of the segments being connected to a 
corresponding cylinder. As the distributor ring revolves the 
segments come into contact with the brush in the proper order. 
The magneto is stationary and is supported by a bracket in an 
inverted position. A pinion on the magneto shaft meshes with 



GAS, OIL AND STEAM ENGINES 



143 



a large gear mounted on the revolving crank case so that the 
armature of the magneto always bears a positive relation to the 
piston position. As the engine requires seven sparks for every 
two revolutions, or Z l / 2 sparks per revolution it is evident that 
the magneto must turn 175 times as fast as the engine, if the 
magneto is of the ordinary type that generates two sparks per 
revolution. In other words the magneto speed is to the en- 
gine speed as 7 is to 4. * 




The "Indian" Rotary Aero Motor. 

The arrangement of connecting rods is interesting, the big 
end of one rod being formed into a cage for the reception of 
the crank-pin ball race. The outer circumference of the cage 
carries the pins to which the other six connecting rods are 
fastened. It is necessary that one rod be integral with the 
cage to prevent its rotation in regard to the cylinders. An- 
nular ball bearings are used on both the main bearings, for 
the thrust bearing to take the thrust of the propeller, and on 
the large end of the master connecting rod. The large ends 
of the auxiliary connecting rods and the small ends of all the 
rods have plain bearings. 



CHAPTER VI 
TWO STROKE CYCLE ENGINES 

(30) The Junker Two Stroke Cycle Engine. 

The Junker two stroke cycle engine stands unique among 
the large stationary units not only in the principle of its work- 
ing cycle but in its construction as well, and while it may be 
considered freakish when compared to standard practice it has 
proved its value in many European installations. The combus- 
tion occurs in the center of an open ended cylinder between two 
pistons that are forced in opposite directions by the expansion 
of the gas, and as there is a single acting piston in each end 
of the cylinder at the end of the stroke, there is no need of 
stuffing boxes, cylinder heads or valves. 

It is apparent that by moving the pistons in opposite direc- 
tions, the effective piston velocity is twice that of the actual 
velocity of either of the pistons, and that it is therefore possi- 
ble to gain a high heat efficiency at high piston velocities with 
a low rate of rotation. The double pistons increase the scaveng- 
ing effects, reduce the losses to the cooling water and increase 
the efficiency at light loads. A marked reduction in weight over 
the four stroke cycle engine is made possible because of the 
absence of valves and valve gear. 

This engine is of the injected fuel type that is the fuel is 
sprayed into the combustion chamber after the completion of 
the compression stroke in a manner similar to the Diesel en- 
gine. By prolonging the injection of fuel after the piston has 
started on the outward working stroke it is possible to main- 
tain the maximum pressure due to the combustion for a con- 
siderable period. This gives an indicator card that is very 
similar to that of a steam engine as the flat top of the Junker's 
card due to the continued combustion and pressure corresponds 
to the admission line of the steam engine. As ignition is caused 
by the high temperature of the compression, almost any low 
grade oil may be used even down asphaltum oils and coal tar. 

In Fig. 8 five piston positions corresponding to five events are 
shown by the diagrams a, b, c, d, e. From the diagrams one 

144 



GAS, OIL AND STEAM ENGINES 



145 



may also get an idea of the arrangement of the principal parts 
of the engine and their relation to one another. P and P2 arc 
the two pistons, C the open ended cylinder, G the connecting 
rod of the inner piston P, H-H the two connecting rods of the 




-79^-7 






z ^r^ r" —^ • 




Fig. 8. The Junker Two Stroke Cycle Engine. 

piston P2, I-I the side rods of the piston P2, and V is the three 
throw crank shaft which is acted on by the' three connecting 
rods H-H-G. The piston P2 is connected to the side rods 
through the yoke Y. It will be noted that the crank throws 



146 GAS, OIL AND STEAM ENGINES 

controlling the piston P2 are 180° from the crank connected to 
piston P, which causes the pistons to move in opposite direc- 
tions. 

With the pistons together at the inner dead center, the space 
between them is rilled with highly compressed air from the pre- 
vious combustion stroke. At this point the fuel is injected into 
the highly heated air, and the expansion of the charge begins, 
the combustion proceeding under constant pressure during the 
first part of the stroke, or during that part of the stroke in 
which the fuel is admitted to the cylinder. When the supply of 
fuel is cut off the working stroke continues by the increase of 
volume, or expansion of the gas, the gases being reduced to 
nearly atmospheric pressure at the end of the stroke with the 
pistons at the position shown by diagram (b). At this point 
the piston P is just opening the edge of the exhaust port M, 
allowing the products of combustion to escape to the atmos- 
phere through the annular exhaust passage that surrounds the 
port M. 

As the pistons continue to move outwards the gases continue 
to issue from the exhaust port at practically atmospheric press- 
ure until the position shown by diagram (c) is reached by piston 
P2. At this point P2 is just opening the inlet port N allowing 
fresh air to enter the cylinder for the purpose of scavenging the 
engine. The passage of the air through the intake port N and 
out through the exhaust port M continues until the pistons pass 
the outer dead center, shown by diagram (d), and begin to 
come back on the return stroke. In diagram (e) the pistons 
have traveled far enough to close both ports, and as the space 
between them is filled with pure air from that furnished by 
the port N, the pistons will continue to move toward one an- 
other on the compression stroke. When they have reached the 
end of their travel as shown by diagram A, the fuel is injected 
into the cylinder and combustion occurs due to the temperature 
of the high compression temperature. 

This is the complete cycle of events made in two strokes, 
and it will be noted that the cycle has been accomplished with- 
out the use of valves. The compressed air for scavenging the 
cylinder is provided by air pumps that are driven from the con- 
necting rods by a link motion. One low pressure pump for 
the scavenging and one high pressure pump for spraying the 
fuel into the cylinder against compression are provided. As 
the inside of the piston is always exposed to the atmosphere 
through the open ends of the cylinder and is never exposed 



GAS, OIL AND STEAM ENGINES 



147 



to the heat of combustion, perfect cooling is secured, and as a 
matter of course, perfect lubrication. 

In the two cylinder engine in which four pistons are used, 
the cylinders are arranged in tandem with the two adjacent 
pistons, and the two outer pistons connected respectively. In 
fact the second cylinder pistons are duplicates of those just 
shown and are connected to the linkage in such a manner as 
to have the corresponding pistons in one cylinder act with 
the corresponding pistons in the second. 

(34) Koerting Two Stroke Cycle Engine. 

One of the most prominent of the two stroke cycle scaveng- 
ing engines built for heavy stationary service is the Koerting 
engine. Because of its peculiar scavenging arrangement, and 




Fig. F-ll. Koerting Two Stroke Cycle Engine with Scavenging and 
Charging Cylinders. 



as it is of the double acting type, it will serve to illustrate the 
cycle of that class of engine equipped with independent air 
pumps. Several of these engines are in use in Europe that 
have an output of over 4,000 horse-power, the general arrange- 
ment of which is the same as shown in the accompanying dia- 
gram Fig. F-ll. 

Since the engine is double acting, two similar combustion 
chambers are provided at each end of the piston as shown by 
C and Ci, and as each of the chambers gives one impulse per 
revolution because of the two stroke cycle, the single cylinder 
shown in the figure delivers two impulses per revolution to the 
crank-shaft. In order to have one exhaust port serve for both 
combustion chambers, the annular port E is placed in the cen- 
ter of the cylinder so that it is alternately opened to C and then 
G as the piston travels to and fro, the port being covered by 



148 GAS, OIL AND STEAM ENGINES 

the piston at intermediate points in its travel. As the piston 
must cover the port for a considerable portion of the stroke, 
it is made very long, nearly as long as the stroke. The piston 
rod R that connects the piston with the crank passes through 
the cylinder head of chamber Q, surrounded by a gas tight 
packing that prevents the leakage of the charge from G. 

Unlike the ordinary type of two stroke cycle engine, the two 
combustion chambers are provided with mechanically operated 
inlet valves, V-Vj-Va-Va that are opened at definite points in 
the s*troke by the lay shaft X which is driven from the crank 
shaft. As the exhaust port E serves all of the functions of an 
exhaust valve, there are no valves provided at this point. Ex- 
haust pipes connected to E carry the burnt gases to the atmos- 
phere. 

Two auxiliary air pumps of the double acting type are pro- 
vided, shown at A and A 2 , one pumping gas and the other air. 
They are driven from the crank-shaft through the connecting 
rod Y, and are proportioned so that together they force a mix- 
ture of the correct proportion for complete combustion into the 
working cylinder at a pressure of about ten pounds per square 
inch. Air and gas are compressed on one side of each pump 
piston in the spaces B and B 2 , and the air and gas are drawn 
in on the other side as at H and H 2 . The connections from the 
compressor cylinders to the working cylinder are arranged so 
that the two crank ends of the compressor cylinders discharge 
into the crank end of the working cylinder, and the front ends 
of the compressors discharge into the front end of the working 
cylinder, the exact moment of discharge being controlled by 
the inlet valves V-Vi-V 2 -V 3 . The pumps are arranged so that 
only pure air is admitted at first in order to force the products 
of combustion through the exhaust port so that they will not 
contaminate the following mixture of air and gas. The inlet 
valve opens immediately after the piston of the working cylinder 
uncovers the port E and reduces the pressure of the burnt gases 
to that of the atmosphere. 

By the action of the admission control, the scavenging air 
first admitted, is prevented from mixing with the residual gas 
from the previous explosion, and in the same way the device 
prevents the loss of fuel through the exhaust ports, thus over- 
coming the principal objections of the simple two stroke types 
described earlier in this chapter. The compressor cylinders pro- 
vide only enough air and mixture for one stroke and no reser- 
voir is provided for a surplus of air or mixture. 



GAS, OIL AND STEAM ENGINES 149 

As the piston moves forward, on the compression stroke and 
covers the exhaust port, the inlet valves also close, and the 
compressor pistons arrive at the end of their stroke so that 
no more air or mixture is delivered to the inlet valves. At the 
end of the compression stroke ignition occurs and the ex- 
pansion or working stroke begins. The piston again moves to 
the right on the working stroke until the front edge uncovers 
the port E where the exhaust gases escape to the atmosphere. 

The valve gear on the gas compressing cylinder is arranged 
so that no gas is delivered to the inlet valves of the working 
cylinder until the air cylinder has provided sufficient air to in- 
sure perfect scavenging of the products of combustion, this pre- 
venting the fuel from becoming contaminated with the burnt gas. 
Speed regulation for varying loads is effected by shifting the 
valve gear of the gas pump so that the gas is delivered at an 
earlier or later period in the stroke of the working piston, thus 
causing a variation in the quantity of gas delivered to the work- 
ing cylinder. This is controlled by the governor directly 
on the valve gear of the pump or upon a by-pass in the pump 
cylinder or both. The by-pass, when open returns all of the 
gas in the passage leading to the inlet valve, that is beyond 
a certain pressure to the cylinder, so that the gas is delivered 
to the cylinder at a constant pressure, and therefore in propor- 
tion to the load and point of cut off. 

This method of governing produces a mixture that varies in 
richness with the different loads that are carried by the engine, 
but as the air enters the cylinder first and is prevented from 
mixing to any extent with the gas by the shape of the cylinder 
heads, the igniting value of the mixture is not disturbed par- 
ticularly as the rich gas remains in the cylinder heads and in 
contact with the igniters. 

Like all large engines, the Koerting is started by compressed 
air taken from a reservoir. A special starting valve is provided 
for each end of the cylinder which is operated from the cam 
shaft by means of an eccentric. The air valves may be thrown 
in or out of gear by a clutch. 

(57) Two Stroke Cycle Rail Motor Cars. 

A unique application of the two stroke cycle motor will be 
seen in Fig. 56 which shows a Fairbanks-Morse two stroke 
cycle motor direct connected to the driving wheel of a railway 
motor car. The three cylinders are mounted between the 
driving wheel with the ends of the axle terminating in the 



150 GAS, OIL AND STEAM ENGINES 

crank cases of the motors. Access to the bearings is had 
through a cover on the crank-case. The simplicity of this 
motor and its freedom from valves, cams, springs, gears, and 
other trouble causing parts makes it particularly adapted for 
the service that it performs in the hands of unskilled track 
laborers. As there is no water to freeze or leak, and as the 
lubricant is mixed with gasoline, the car needs very little more 
attention than the old type hand car. 

The car is started by opening the gasoline supply cock, clos- 
ing the ignition switch, and pushing the car along the track 
until the first explosion occurs. The speed is controlled in the 
usual manner by means of the spark advance and throttle. As 
the motor is of the two stroke cycle type, it may be reversed 




Fig. 56. Two Stroke Cycle Fairbanks Motor for Driving Railway 

Section Cars. 

by simply changing the position of the timer without the use 
of the gears. The speed is the same in either direction. By 
the use of three cylinders; three impulses are obtained per revo- 
lution which gives a distribution of power equal to that of the 
ordinary six cylinder, four stroke cycle automobile motor. 

For larger cars built for carrying large gangs of men, a three 
cylinder motor is used which drives through a clutch and gears, 
similar to that used on automobiles. It is located near the 
center of the axle and is supported on a frame that is independ- 
ent of the car proper. This motor unit is easily removed from 
the car for inspection with all of trre parts intact. A universal 
coupling is provided on the motor shaft to prevent strains due 
to changes in the alignment from being thrown into the motor. 
The motor of this car is started with a crank, and may be left 
standing with the motor running. As with the two cylinder 
car, the engine is reversible, and is lubricated by mixing the 
lubricating oil with the gasoline. 



GAS, OIL AND STEAM ENGINES 



151 



(58) Rotating Cylinder Two Stroke Cycle Motor. 

An unusual type of two stroke cycle engine is that designed 
by M. Farcot for aeronautic work. It is of the rotating cyl- 
inder type in which the cylinders rotate about a stationary 




-,-R 



Fig. 63. Farcot Rotary Two Stroke Motor. 



crankshaft, and unlike all previous two stroke motors, whether 
of the revolving or stationary cylinder type, no initial compres- 
sion is performed either in the crank-case or otherwise. 



152 GAS, OIL AND STEAM ENGINES 

Undoubtedly the two-cycle rotating multi-cylinder engine has 
a future when some of the particularly difficult designing prob- 
lems invplved in its production have been successfully tackled. 
Crank case compression has had its devotees, but so far it has 
entailed the use of a low compression, owing largely to the 
difficulties involved in lubricating the bearings and maintain- 
ing gas-tight joints, besides other defects. Some of these bar- 
riers appear to have been surmounted in this design. 

Fig. 63 of the accompanying drawings is a sectional side ele- 
vation of the engine, which, it will be seen, is similar in gen- 
eral disposition to the usual arrangement of the rotating cyl- 
inder type. In this particular case, however, the short end A 
of the stationary crankshaft is reduced in diameter at B, and 
on this part are mounted ball bearings C carrying the circular 
casing of a rotating centrifugal blower D. To the inner end 
of the hub of this blower is attached a gear wheel E, the teeth 




r 

Fig. 64. Farcot Fan Plates. 

of which mesh with small intermediate pinions carried on a 
spider F attached to the crankshaft. These pinions are in 
turn driven by an internally toothed ring G attached to the 
hub of the crank case H. Thus the blower D is driven in the 
opposite direction to the crank-case and at a higher speed. In 
the interior of the blower casing radial blades K are provided. 

A hollow annular casing L is bolted to the cylinders, and 
communicates with their interiors by means of inlet ports M 
covered and uncovered by the pistons. 

The blower casing D has on either side circumferentially 
flanged rings N, which are a running fit in circular register 
slots provided in the annular casing L and its cover plate P, 
in order to provide a gas-tight joint between the opposite re- 
volving casings D and L. Fan blades Q are also provided in 
the casing L to accelerate still further the incoming gas. The 
arrangement of the two sets of blades is made clear in the 
sectional sketch (Fig. 64). It will be realized that by means of 
this compound blower device a considerable pressure can be 
attained. 

The crankshaft is drilled to provide a feed for the gasoline, 



GAS, OIL AND STEAM ENGINES 153 

which is atomized by a device R in the large central opening 
of the blower casing D by means of pressure fed from the 
annular casing L through suitable leads S. 

As each piston nears the bottom of its stroke, exhaust ports 
T, provided with expansion cones for the purpose of increasing 
the velocity of the exhaust gases, are opened. The inlet port 
M is then uncovered, and the compressed charge rushes into 
the combustion chamber. 

The general design of the engine is made plain by Fig. 63, 
but there is one other point to which reference should be made, 
and that is the provision of rings V, one on either side of the 
cylinders, to enhance the strength of the construction. 

Although the difficulty of compression appears to have been 
cleverly tackled in this invention, the possibility of the com- 
pressed mixture in the inlet casing and blower. becoming ignited 
at the moment of admission by a residue of exhaust gas in the 
combustion chamber still exists. However, the effect of such 
a backfire should not prove quite so serious as in some de- 
signs. Apart from other considerations, owing to the large 
area of the blower intake, such an occurrence should merely 
have a more or less elastic braking effect. 

(60) Gnome Radial Two Stroke Motor. 

The builders of the famous Gnome four stroke cycle rotary 
motor, Sequin Freres, have recently developed a radial two 
stroke cycle motor that bids fair to supplant their original type. 
Referring to the diagramatic cross-sections which show only 
a single cylinder unit, a very long tubular piston will be seen 
that is divided into two independent chambers, A and B. Both 
chambers are placed in communication with the outside space, 
C and D. 

The upper end of the piston is continued above the top divi- 
sion head of the chamber A, and the extension is provided with 
the slot F. Near the center of the piston, the walls of the 
piston are run out into a flat circular plate or trunk piston E, 
which is the actual piston head that receives the force of the 
explosion. The piston E reciprocates in the large cylinder H, 
which is reduced at its upper end to the diameter of the main 
piston barrel, for which it affords a sliding support, or guide, 
and also serves to aid the exhaust port closure. The lower 
end of the cylinder H is enlarged in diameter as shown by K 
so that a clear annular space is left between the cylinder walls 
and the piston head E, when the latter is at the bottom of the 



154 



GAS, OIL AND STEAM ENGINES 



stroke. The cylinder diameter is then reduced to the diameter 
of the main piston barrel. 

The motor operates as follows: 

Suppose the piston to be ascending (Fig. 1), compressing the. 
mixture above the piston head in the cylinder E, and at the 
same time the volume of the space M, below E, is being in- 
creased until the piston reaches the position shown in Fig. 2. 

Referring to Fig. 1; the interior chamber A of the piston is 
in direct communication through the holes C with the space 




Fig. 65. Gnome Rotary Two Stroke Motor Diagram. Diagrams 1 and 2. 

M, consequently as the piston goes up, a partial vacuum will 
be formed in these two chambers. When the piston reaches the 
top of its stroke as shown in Fig. 2, the holes D in the lower 
end B of the piston are uncovered as they rise into the in- 
creased diameter of the cylinder, and therefore the mixture is 
sucked in from the crank case until the chambers A and M are 
filled to atmospheric pressure. 

The spark now occurs at the plug S, and the explosion takes 
place, driving the piston downwards as shown by Fig. 3, just 



GAS, OIL AND STEAM ENGINES 



155 



before the exhaust takes place. The volume of the chamber 
M has now been decreased with the result that the mixture will 
have been compressed into the chamber A. 

In Fig. 4, the piston has now reached the bottom of the 
stroke, and the ports F have opened as the slots carry below 
the upper end of the cylinder where the bore is increased. At 
the same time, as the piston plate E passes the bottom of the 
cylinder H into the enlarged diameter K, the compressed mix- 
ture in A and M rushes through the annular space opened 




Gnome Rotary, Diagrams 3 and 4. 

around E into the combustion chamber and drives out the 
residual burned gases which still remain after the explosion. 
On starting the second revolution the piston rises and the 
cycle repeats as shown by Fig. 1. 

This engine may be built with any number of the cylinder 
units described, preferably with an uneven number, as in the 
case of the Gnome radial four stroke cycle, and with twice the 
number of impulses of the four stroke type a very uniform 
turning movement should be had. 



156 GAS, OIL AND STEAM ENGINES 




Fig. 64-b. Roberts Two Stroke Aero Motor Using a Rotating Tubular 
Valve that Controls the Mixture from the Carburetor so that it 
Enters Only One Crank Case at. a Time. This Gives Each Cylinder 
an Equal Charge of Gas. 





Fig. 64-c. Roberts Distributor Valve. The Ports Are Cut in the Valve 
so that Only One Crank Case is in Communication with the Car- 
buretor at Any One Time. The Central Hole Connects with the 
Carburetor. 



GAS, OIL AND STEAM ENGINES 



157 



Since the valves are the parts that give the most trouble 
in the four-stroke cycle Gnome, this motor should be better 
adapted for aviation than the original type of Gnome. 

(62) Variable Speed Two Stroke Motor. 

A variable speed two stroke cycle motor is described by 
C. Francis Jenkins in the Scientific American that seems to 




Fig. 66. Jenkins Two Stroke Cycle Motor. 



solve many of the problems encountered in designing a two 
stroke cycle motor for automobile purposes. As is well known, 
the present design of the crank-case compression type is waste- 
ful of fuel, and ignites irregularly at low speeds and light run- 
ning, and as nearly all automobiles are well throttled for a 
greater portion of the time it means that this type of motor 
is working under the greatest disadvantage. 

Since the greater part of the trouble is due to the dilution of 
charge by the residual gases, and as the spark plug of the 



158 



GAS, OIL AND STEAM ENGINES 



motor is situated in the most diluted portion of the gas, it 
would seem that a change of spark plug location, or a change 
in the circulation of the fresh mixture in the cylinder would be 
a great aid in remedying the difficulty. With the spark con- 
tinually in contact with fresh undiluted mixture it would be 
possible to run it as low speeds as with the four stroke motor, 
with a corresponding increase in the efficiency, and opportunity 
to run with a constant advance of the point of ignition. This 
is accomplished by any or all of the following conditions: 

(1.) By keeping good gas separate from bad. 

(2.) By placing the spark near the intake port. 

(3.) By leaving the plug in its present position and deflect- 
ing the fresh gas to meet it. 

(4.) By changing the location of the inlet port. 




Fig. 58-a. 



Two Cylinder Marine Engine, of the Two Stroke Type. 
Built by Fairbanks-Morse and Company. 



In the motor invented and described by Mr. Jenkins, the 
method given by (4) is adopted as shown by Fig. 66, in which 
the spark plug is placed at the point of admission of the gas 
and in a confined passage. The operation of the motor is 
as follows: 

Carbureted gas is drawn into crank-case from the carburetor 
(not shown) in the usual manner, i. e., by the upward move- 
ment of the piston; and by its downward movement is forced 
through the rectangular port in the wall of the piston into the 
combustion passage within the water-jacket when the port in 



GAS, OIL AND STEAM ENGINES 159 

the piston wall registers with the lower end of this combustion 
passage, and drives ahead of it the bad gas remaining after the 
previous explosion. If. the throttle is wide open the combus- 
tion space above the piston will be completely filled, and on the 
ignition of the charge the maximum pressure will be exerted on 
the piston. If, however, the throttle is but slightly open, the 
combustion passage only may be filled and none overflow into 
the combustion space above the piston. This small charge will 
be just as efficient in proportion to its volume as was the large 
charge, for it was compressed to practically the same extent and 




Fig. 64-d. Roberts Cylinder Showing Cellular Screen in the Intake 
Port. This Screen Prevents Crank Case Fires by Chilling the Cyl- 
inder Flame Before it Enters the Crank Case. 

none was mixed with the bad gas of the previous explosion. 
It will, therefore, be obvious that the spark-plug is always swept 
by the fresh charge, be it large or small, and the ignition will 
be just as certain in one case as in the other, although the 
charge and consequent impulse may be only just sufficient to 
keep the engine turning over, and without missing a single 
explosion. 

In the motor built to test and demonstrate this design, 
provision was made for a second spark-plug to be located in 
the top of the cylinder for speed work, if this was found nec- 
essary. No opportunity has yet been had for making track 
tests, though without regret, as this two-cycle motor will run 
idle without missing or "stuttering," which was the thing here- 
tofore impossible. 



CHAPTER VII 
OIL ENGINES 

(31) Diesel Oil Engine. 

The Diesel engine marks the greatest progress in the internal 
combustion field made in the last few years. It marks a dis- 
tinct advance in both thermal efficiency, and in the character 
of the fuel that it has made a commercial possibility. By the 
use of cheap fuel heretofore unavailable for any type of prime 
mover, such as the asphaltum residual oils, coal tar, etc., it 
has lowered the cost of power production to a point where it 
is unapproached by any type of heat engine. Besides its thermal 
efficiency, the engine is free from the annoyances due to delicacy 
of the auxiliary appliances such as the carburetor, and ignition 
system which are indispensable with the ordinary type of gaso- 
line engine. 

This engine belongs to that type of engine in which combus- 
tion takes place at constant pressure (Brayton Cycle), that is 
the combustion pressure is maintained at a constant value for 
a considerable distance on the working stroke of the piston. 
This method differs from the Otto cycle in which the combus- 
tion proceeds at a constant volume, or the type in which com- 
bustion is completed before the piston moves forward on the 
working stroke. 

In the Diesel cycle the first stroke of the piston draws pure 
air into the cylinder; the piston then moves forward on the 
compression stroke, compressing the air to 500 or 600 pounds per 
square inch and raising the temperature of the air to about 1,000 
degrees C, the exact temperature and pressure depending on 
the character of the fuel used in the engine. The high pressure 
is obtained by using a small clearance space in the end of the 
cylinder. At the end of the compression stroke a spray of oil 
is injected into the cylinder which is instantly ignited by the 
high temperature of the compressed air. 

The oil continues to burn as long as it is sprayed into the 
cylinder, this period being from one-quarter to one-third of 
the working stroke. After the oil is cut off, the hot gas is ex- 

160 



GAS, OIL AND STEAM ENGINES 



161 



panded to the end of the stroke at which point the pressure is 
very considerably reduced due to the mechanical work per- 
formed. It should be noted that the type of engine just de- 
scribed performs the complete cycle in four strokes, the fourth 
stroke being the scavenging stroke as in the ordinary four 
stroke cycle engine. While the four stroke cycle type of Diesel 
engine is by far the most common type, it is also built as a two 
stroke cycle that is similar to the two stroke cycle gas engine 
previously described except that pure air is received and com- 
pressed in the air compressor in place of the combustible mix- 
ture. 

It will be noted, that as there is no fuel in the cylinder dur- 
ing the compression stroke that there is no danger from pre- 
ignition from an over heated charge, nor is there trouble from 




Fig. 9. 



Cross Section of Four Stroke Cycle Diesel Engine. 
Valve is the Fuel Admission Valve. 



The Center 



decomposed fuels due to a gradually increasing temperature so 
often met with in oil engines that compress the entire mixture. 
As the clearance space is exceptionally small there is a minimum 
of residual gas held in the cylinder after the explosion with the 
result that the fuel is completely consumed, and that a full 
charge is taken into the cylinder. 

The speed and output are regulated by controlling the point 
in the working stroke at which the oil spray is cut off, and as 
this has no effect on the maximum pressure developed in the 
cylinder, as in the case of the ordinary gas engine control, the 
pressure charge under varying loads is not so severe. Be- 
cause of the high compression, and the continued combustion, 
there is a very gradual increase of pressure. Since the amount 
of pure air admitted to the cylinder is the same at no load as 
at full load there is always sufficient air for the complete com- 
bustion of the fuel, and as there is a constant compression 



162 



GAS, OIL AND STEAM ENGINES 



pressure there is a constant ignition temperature and constant 
quantity of the working medium. Because of the high com- 
pression obtained by the Diesel type, it has an efficiency that 
is far beyond that of any other form of internal combustion 
motor. 




Fuel Nozzle of the Koerting Diesel Engine Showing Operating Cam and 
Lever, and Compressed Air Connection. 



Since the fuel is introduced gradually into the combustion 
chamber the combustion pressure rises very slowly so that it 
is not an explosive engine in any sense of the word, the com- 
bustion pressure rising steadily from the compression pressure 
to the maximum in porportion to the supply of fuel. In the 
ordinary type of gas engine with a compression pressure of 
from 60 to 70 pounds per square inch the pressure rises abruptly 
to about three and one-half times the compression pressure, 



GAS, OIL AND STEAM ENGINES 



163 



with a correspondingly rapid drop in the pressure on the ex- 
pansion stroke. In the Diesel engine the drop of pressure in 
expansion is much more gradual, the indicator diagram expan- 
sion curve being nearly horizontal. The uniform pressures thus 
obtained result in smooth action and even driving power, ob- 
tained with no other type of engine. 




Fuel Pump of Koerting Diesel Engine with Operating Cam. 

As the fuels used vary from the lightest hydrocarbons to the 
heaviest crude oils, there are many types of oil injection valves 
in use, the valves being in general divided into two classes, 
those in which the oil is vaporized mechanically by the pres- 
sure of a force pump, and those in which the fuel is vaporized 
by the atomizing effect of compressed air. Atomization by com- 
pressed air is however, the most common method since less 
trouble is experienced with the air pumps than with the liquid 
force pumps. The compressed air is supplied by pumps that 



164 GAS, OIL AND STEAM ENGINES 

are either operated by the main engine or by an independent 
compressor engine. 

The fuel valve is a plug screwed into the cylinder containing 
an inwardly opening check valve in the inward end. The hole 
in the center of the plug receives the oil charge under a few 
pounds pressure from the tanks, during the compression stroke 
of the engine, and at the end of the compression stroke, a blast 
of air at a pressure of about 250 pounds above the com- 
pression pressure blows it into the cylinder in the form of a 
fine spray. Injection valves of the forced feed type consist of 
a plug with a small passage and a needle valve for regulating 
the spray. Fuel is pumped into the valve at about 250 pounds 
above the compression pressure of the engine by a small single 
acting pump which is built so that the length of the stroke 
may be adjusted to meet the load. In practice the length of 
stroke is regulated by the governor, so that the full contents 
of the pump are delivered at full load, and a reduced amount 
with a short stroke at small loads. On issuing from the fuel 
nozzle, the liquid strikes a gauze screen by which it is broken 
up into very fine spray. 

Fluidity is practically the only factor that governs the quality 
of fuel that may be used with the engine, since exceptionally 
heavy oils and tars cannot be successfully sprayed. In Fig. 9 
is shown a cross-section of a Diesel engine cylinder in which 
the center valve in the cylinder head is the fuel valve, and the 
valves to the right and left are the air inlet and exhaust valves 
respectively. The two latter valves correspond to the inlet and 
exhaust valves of the Otto cycle engine. 

Compressed air is used in starting the engine, which is ad- 
mitted to the cylinder through an auxiliary valve which is oper- 
ated by a starting cam on the cam shaft. By this mechanism, 
high pressure air is furnished to the cylinder during a portion of 
the working stroke, turning it over on the first few revolu- 
tions as a common air engine. As soon as the engine picks up 
speed, the starting valves are thrown out of operation, and 
the engine proceeds on its regular working cycle with the 
oil fuel. 

When used for marine purposes in sizes over 100 horse-power, 
where it is not possible to use reverse gears, the Diesel engine 
whether of the two stroke cycle or four stroke cycle type must 
be made reversible. This may be accomplished by either of 
two methods, first, by changing the angular position of the 
cams in regard to the piston, position, and second by using two 



GAS, OIL AND STEAM ENGINES 165 

sets of cams, one being for right hand rotation and the other 
for left hand. When a single cam is used, the relation of the 
cam shaft on which the oil pump cams and oil valve cams are 
located, is advanced or retarded in respect to the crank shaft 
by means of sliding the two spiral gears that drive the cam 
shaft, over one another, in a direction parallel to their axes. 
The spiral gears are moved back and forth by a hand controlled 
reverse lever. This type is used principally on the two stroke 
cycle type of engine as there are not so many factors to con- 
tend with as on the four stroke cycle. 

With double cams, the system almost invariably used with the 
four stroke cycle engine, the cams may be mounted either on 
one shaft, or the ahead cams on one cam shaft and the reverse 
cams on another. When two shafts are used they are arranged 
so that either set of cams may be swung under the valve lifters 
by swinging the shafts in a radial direction by brackets. The 
single type of cam shaft is usually moved back and forth in 
a direction parallel to its axis, the ahead cams coming under 
the valve lifts at one position, and the reverse cams at the 
other. In the four stroke cycle Diesel it is evident that not 
only the relations of the oil pump and oil valves must be 
changed in respect to the piston position but the relations of 
the air inlet and exhaust valves must be changed as well. This 
necessitates double cams for the inlet and exhaust valves in 
order to reverse rotation. 

Compressed air for starting and injection is generally supplied 
by a three stage air compressor or a compressor in which the 
pressure is built up in three different steps, the second cylinder 
taking the air from the discharge of the first, and the third 
cylinder taking the air from the second, and compressing it 
to about 250 pounds above the compression pressure of the en- 
gine. Perfect scavenging is possible with this engine because 
of the large excess of air supplied during the suction stroke 
and the period of injection. On the marine type the air pumps 
and water circulating pumps occupy about the same amount of 
space as the condenser and circulating pumps of a steam engine 
having the same outputs. In a recent test made with an Atlas- 
Diesel engine it was found that 11 per cent of the output was 
lost in driving the air pumps or more than 50 per cent of the 
total loss by friction and impact. 

Unlike the ordinary gasoline engine in which an increase of 
speed increases the output in an almost direct proportion, the 
output of the Diesel engine decreases when the speed rises 




Fig. 67. Cross-Section Through the Working Cylinders of the M S. 
Monte Penado Two Stroke Cycle Diesel Engine. From the Motor 
Ship, London. 



GAS, OIL AND STEAM ENGINES 167 

beyond a certain limit clue to imperfect combustion at speeds 
much over 350 revolutions per minute. Because of this fact it 
has been practically impossible to apply the type to automobile 
service which ordinarily requires a speed of from 400 to 800 
revolutions per minute under ordinary conditions. In addi- 
tion to the speed limitations, the Diesel engine weighs approxi- 
mately 70 pounds per horse-power against an average weight of 
17 pounds per horse-power with the ordinary type of gasoline 
automobile motor. Of course these objections may be over- 
come in time, as the engine is only in its infancy, and the two 
stroke cycle Diesel has not yet been fully developed, but at 
the present time it does not seem probable that this engine will 
ever be an active competitor of the gasoline automobile motor, 
at least from the standpoint of flexibility. 

As the Diesel engine depends entirely upon compression for 
its operation, it is necessary that all of the parts such as the 
pistons, valves, etc., shall be perfectly fitted and air tight under 
extremely high pressures. The careful workmanship required 
for such fitting and the adjustments make the Diesel much 
more expensive to build than the ordinary type of gas engine, 
and for this reason the first cost and overhead charges cut into 
the fuel item to a considerable extent. A description of the 
Diesel engines will be found in the chapter devoted to oil 
engines. 

(63) Diesel Engine (Marine Type). 

As a practical example of a Diesel engine, which was de- 
scribed in Chapter III, we will give a brief description of the 
two 850 horse-power Diesel engines installed in the cargo 
vessel "M. S. Monte Penedo," which were built by Sulzer 
Brothers of Wintherthur, Switzerland. We are indebted to the 
Motor Ship, London, for the details. 

The engines are of the two stroke cycle, single acting type, 
with four working cylinders, a double acting scavenging pump 
cylinder, and a three stage ignition compressor cylinder. The 
bore of the working cylinders is 18.8 inches, and the stroke 27 
inches. While the crank case is of the enclosed type, there 
are two sets of covers which can be easily removed for in- 
spection while the engine is running, for as the scavenging 
pump performs the work of the crank case of the ordinary two 
stroke cycle engine there is no need of a tight case to retain 
the compression. 

The scavenging pump is mounted on one end of the engine 



168 



GAS, OIL AND STEAM ENGINES 




Fig. 68. Cross-Section Through the Air Cylinders of the Two Stroke 
Diesel Motors on the M. S. Monte Penado. 



GAS, OIL AND STEAM ENGINES 169 

and is driven from the crank-shaft, the cross-head of the pump 
forming one piece with the piston of the low pressure cylinder 
of the injection air cylinder. All of the compressor stages arc 
water cooled and fitted with automatic valves. The double act- 
ing scavenging pump has a piston valve driven by a link mo- 
tion for reversing it when the engine is reversed. The air 
enters the pump through the top valve chamber from a pipe 
leading into the engine room. The air discharges a pressure 
of about 3 pounds per square inch in a header that passes in 
front of all four working cylinders. By means of a valve the 
air entering the low pressure stage of the compressor can be 
taken either from the atmosphere or from the discharge of the 
scavenging pump; taking the air from the latter allows of a 
greater weight of air taken by the compressor and consequently 
a higher compression for use in emergencies. 

As in the ordinary type of two stroke cycle engine, two in- 
dependent sets of exhaust ports are used, one set being for the 
scavenging air and the other for the exhaust gases, both sets 
being at the end of the stroke as usual. The air inlet ports are 
divided into two groups, however, one group being controlled 
by the piston of the working cylinder, and the other group by 
an independent piston valve driven from the cam-shaft. Both 
sets of ports connect with the main scavenging air header. By 
means of the valve controlled ports it is possible to admit 
scavenging air even after the other ports are closed by the 
piston, which greatly increases the scavenging effect. With 
the air at 3 pounds pressure the air from the valve controlled 
ports throw the scavenging air to the top of the cylinder even 
after the exhaust ports are closed. This valve is provided with 
a reverse mechanism. A single cam is used for operating the 
fuel inlet valve and the air starting valve, and the reversal of 
the engine is obtained by turning the cam shaft through a small 
angle relative to the crank-shaft, which of course also reverses 
the lead of the fuel valve. Starting is accomplished by com- 
pressed air, with the air valve lever on the cam, and the fuel 
valve lever off. After turning through a few revolutions, the 
air valve levers are raised, and the fuel levers dropped back on 
the cams which results in the engine taking up its regular cycle. 
' By moving the tappet rod of the fuel valve out of or into 
a vertical position, the time of the fuel valve opening is reg- 
ulated and the amount of air is controlled. This movement is 
normally performed by a compressed air motor, but in an emer- 
gency hand wheels may be used. 



170 GAS, OIL AND STEAM ENGINES 

One of these serves to rotate the camshaft through the re- 
quired angle in order to set the cams in the positions for astern 
or ahead running and also reverses the link motion of the 
scavenging pump valve by the rotation of shaft, as mentioned 
above. The other auxiliary motor operates the fuel and starting 
air valves by moving the small spindle longitudinally to bring 
the tappet lever of the air valve about the required cam for 
ahead or reverse and also lifts this or the fuel valve tappet rod 
off its cam, according as it is desired to run on fuel or air. 

The spindle on which the valve levers are pivoted is in two 
parts, divided at the center. This is to allow two of the cyl- 
inders to run on air whilst the other two are running on fuel, 
and, as can be seen from the dial where the pointer indicates 
the position, in starting up, whether astern or ahead, first two 
cylinders are put on air, then four on air, next two on air and 
two on fuel, and finally all four on fuel. This allows very 
rapid attainment of full speed. 

The amount of fuel entering each cylinder can be regulated 
separately by small hand wheels. 

Below the fuel pumps are arranged three auxiliary pumps, 
two of these being oil pumps for the oil circulation, whilst the 
other is of the piston cooling water. On the left of the en- 
gine and driven in a similar manner from the cross-head by 
links are three other pumps, one for the circulating water and 
the other for the general water supply of the ship. 

Lubrication for the cylinders is furnished by 8 small pumps, 
just above the water pumps, two oil pumps being provided for 
each cylinder. As the supply pipe is divided into two parts, 
the oil reaches the cylinder at four points in its circumference. 
Four oil pumps are provided for the air compressor. 

Four steel columns are provided for the support of each cyl- 
inder in addition to the cast iron frame of the base, and by 
this means the explosion stresses are transmitted directly to 
the bed plate. The cast iron columns provide guide surfaces 
for the cross-head shoes. The guides are all water cooled. 

(64) The M.A.N. Diesel Engine. 

The Maschinenfabrik Augsburg-Nurnburg, G. A., a German 
firm have built some remarkably large Diesel engines both of 
the vertical and horizontal types. The peculiar merits of the 
horizontal type of Diesel engine of which the M.A.N, company 
are pioneers are still open to discussion at present, but there 
is no doubt but what this type will be the ultimate form of 



(IAS, OIL AND STEAM ENGINES 



171 



vary large engines when certain alterations are made in the 
design. 

In Fig. 69 is shown a 2,000 brake-horse-power horizontal 
M.A.N. Diesel engine of the four stroke cycle type which is 
installed at the Halle Municipal Electricity Works, Halle, Ger- 




Horizontal M. A. N. Diesel Engine at the Halle Municipal 
Plant. 




Fig. 70. High Speed Mirlees-Diesel Engine. 

many. It is of the double acting type with twin-tandem cyl- 
inders giving four working impulses per revolution. This en- 
gine was installed in addition to the six producer gas engines 
already in place to take the peak load of the station at different 
times during the day, the gas engines meeting the normal 
steady demand. 



172 



GAS, OIL AND STEAM ENGINES 



This firm has built many thousands of the vertical type of 
Diesel engine of all sizes, and has recently installed 13 engines 
of 4,500 brake horse-power for operating the Kreff tramways. 
The company is now building cylinders giving outputs of from 
1,200 to 1,500 brake horse-power per cylinder, giving outputs of 
from 5,000 to 6,000 horse-power in tandem twin type engines. 
As will be seen from the cut, the horizontal Diesel engine is 
remarkably free from complicated valve gear. 

(65) Mirlees-Diesel Engines. 

The Mirlees-Diesel engine is built by the English firm, Mir- 
lees, Bickerton and Day both for stationary and marine service. 




Fig-. 71. Mirlees-Diesels at Dundalk. 

A generating plant consisting of two, 200 horse-power Mirlees 
engines direct connected to Siemens generators has been in- 
stalled in the municipal plant at Dundalk as shown by Fig. 71. 
On test these units consumed 0.647 pounds of oil per horse- 
power at full load and 0.704 pounds per horse-power at half 
load with a regulation of 3.24 per cent from full load to no 
load. All of the engines built by this firm are of the four 
stroke cycle type. 

(66) Willans-Diesel Engines. 

The Willans-Diesel engines built by the Willans and Robinson 
Company of Rugby, England, are in sizes up to 400 brake horse- 



(J AS, OIL AND STEAM ENGINES 



173 



power, and run at speeds up to 250 revolutions per minute. 
They are all of the four stroke cycle type and are applied prin- 
cipally to the driving of electric generators. The cut shows 
one of the four, 280 horse-power units supplied to the Alranza 
Company and the.Rosario Nitrate Works in South America. 
Unlike the Mirlees engine, the Willans has an individual 
frame for each cylinder as in steam engine practice. Like the 
steam engine frame, the bottom is left open for the inspection 
of the connecting rod ends and the main bearings which is a 
most desirable feature. The air compressor and pumps are 
arranged in a most compact form at the left end of the crank- 




Fig. 72. Willans Vertical Diesel Engine. 

shaft from which the pipes may be seen issuing to the four cyl- 
inders. The valves and over head gear are of the conventional 
type, which, with the exception of a few minor details are the 
same as those on the recently developed Sulzer-Diesel. The 
individual grouping of the cylinder units has many desirable 
features and should, we believe, be more extensively copied. 



(67) Installation and Consumption of Diesel Plant. 

An English gas-electric station was completed at Egham, 
England, that is a good example of the changes that have been 
made recently in the electricity supply abroad, with Diesel 
power. 



174 



GAS, OIL AND STEAM ENGINES 



The generating plant comprises two 94 K. W. Diesel en- 
gines built by Mirrless, Bickerton and Day, direct connected 
to single phase alternators generating at 2,000 volts. The 
exciters are direct connected to the main shaft, and the 
plant is capable of generating an overload of 10 per cent for 
two hours. Space has been left for the installation of two 
more units of a larger size. 

The following fuel consumption was guaranteed for a load 
of unity power factor, and the official tests show slightly bet- 
ter figures than the guarantee. 

Full load 0.68 lb. oil per K. W. H. 

Three-quarter load 0.72 lb. oil per K. W. H. 

Half load 0.79 lb. oil per K. W. H. 

Quarter load 1.15 lb. oil per K. W. H. 



WATER OUTLET 
J^=^^EROM ENGINE 



FAN COOLER-* 



OPEN TOP SUPPLr 
TANK WITH BALL-* 
VALVE CONNECTION 




Cross-Section Through Egham, England Municipal Plant. 



Particular attention has been given to the water supply for 
the jackets of the engines; the circulation being by two elec- 
trically driven, direct connected centrifugal pumps, one of 
which is a spare. A Little Company's cooler has been installed, 
which consists of a horizontal cylindrical chamber, the lower 
part of which contains water. In the tank are arranged a 
number of concentric metal cylinders spaced about Y^-inch 
apart, and in several sections, that are carried on a slowly 
revolving shaft, driven from the fan shaft. The cylinders are 
all of the same length, and are open at both ends. 

The lower half of the cylinders dips into the water in the 
casing, and as they revolve, a thin film of water on each side 
of the plate is carried into the upper portion of the casing 
where it meets a blast of cold air from the fan. The fan is 
driven from the circulating pumps, and passes the air through 



GAS, OIL AND STEAM ENGINES 175 

the chamber in a direction opposite to that of the water, baffles 
being placed so that correct circulation is maintained. 

The small loss is made up by connecting the ball cock in 
the tanks with another tank charged from the works well by 
means of a self-starting rotary pump, electrically driven. Very 
little power is required for the pumps and cooler. Fuel oil is 
stored in a tank outside the building, the oil being supplied 
to the tanks from an oil wagon by means of a small hand pump. 

Oil is taken from the tanks and forced into the engine room 
by a rotary pump, from which it enters two graduated tanks 
located in the roof of the station. The graduations on the 
tanks allow the consumption of oil to be carefully recorded 
by alternately filling and emptying the two auxiliary fuel tanks. 

The entire building is electrically heated, and the kitchen of 
the flat above the station is equipped with an electric cook- 
ing-stove for the use of one of the engineers who make it his 
residence, 

DIESEL HORSE-POWER FORMULA 

P. A. Holliday, in the Engineer, derives a new formula for 
computing the horse-power of the four stroke cycle, single- 
acting engine. For each horse-power developed by these en- 
gines about 21,000 cubic inches of displacement is necessary, 
per minute. 

D = Cylinder bore in inches. 
S == Stroke in inches. 
M.P.S. = Mean piston speed in feet per minute. 
R = Ration of stroke to bore. 
N = Revolutions per minute, then 

V B.H.P. X 2220 
D= 



M.P.S. 

6 M.P.S. 
Knowing the value of D, N = 



S 
For high speed, low ratio (R), four stroke cycle engines, 
approximately 22,000 cubic inches displacement per minute is 
required. 

V 2,330 B.H.P. 
D = 



M.P.S. 
In both formulae, the air compressor for fuel injection ia 
included. 



176 GAS, OIL AND STEAM ENGINES 

(32) Semi-Diesel Type Engine. 

In the "Semi-Diesel'' Type Engine the oil is injected into 
the cylinder at the point of greatest compression in the same 
manner as in the Diesel engine, and like the Diesel it compresses 
only pure air. In regard to the compression pressure, however, 
it stands midway between the pressure of the Diesel engine and 
that of the ordinary "aspirating" type oil engine, as the com- 
pression averages about 150 pounds per square inch. While 
this is a much higher pressure than that carried by the ordinary 
kerosene engine which compresses a mixture of kerosene vapor 
and air, it is not sufficiently high to ignite the oil spray by the 
increase in temperature due to the compression, but ignites the 
charge by means of a red hot bulb or plate placed in the com- 
bustion chamber. 

This type of engine is built both in the two stroke and four 
stroke cycle types, the events occurring in the same order as 
in the two stroke and four stroke Diesel types, that is, pure air 
is drawn into the cylinder on the suction stroke (four stroke 
cycle) or is forced in at the beginning of the compression stroke 
(two stroke cycle), and is compressed in the combustion cham- 
ber. At the end of the compression stroke, the fuel is injected 
against the red hot bulb or plate by which the charge is ignited. 
Expansion follows on the working stroke after the fuel is cut 
off, and release occurs at the end of the stroke. 

Fuel oil is supplied to the spray nozzles by a governor con- 
trolled pump having a variable stroke or by compressed air 
as in the Diesel engine, making the supply of fire proportional 
to the load. A separate pump is generally supplied for each 
cylinder, which is capable of developing a pressure of about 
400 pounds per square inch. Several of the Semi-Diesel type 
engines have water sprayed into the cylinder for the purpose of 
cooling the cylinder and piston, and as an aid in the combus- 
tion. This water spray increases the output of a given size 
cylinder by the amount of the steam formed by the heat of the 
cylinder and piston walls, and by the increased rate of combus- 
tion. The amount of water supplied to the cylinder is equal, 
approximately to the amount of fuel oil. The water connection 
is made in the air intake pipe so that the water spray and the 
intake air are drawn into the cylinder at the same time. 

There is very little difference in the efficiency of the Diesel 
and Semi-Diesel in favor of the true Diesel type for both 
have accomplished records of a brake horse-power hour on .45 
pound of crude oil in units of the same capacity. Neglecting 



GAS, OIL AND STEAM ENGINES 177 

the question of efficiency the Semi-Diesel has many advantages 
which are due principally to the differences in compression 
pressures. Valve and piston perfection in regard to leakage is 
not as essential with the semi-type as with the Diesel, as the 
former is not dependent on compression for its ignition. This 
means that the Semi-Diesel has a lower first cost and a lower 
maintenance expense. Its low compression pressure makes 
starting possible without the use of compressed air with engines 
of a considerable horse-power. As the explosion pressure is 
much lower than with the Diesel type there is less strain on 
the working parts and lubrication is much more easily per- 
formed. 

Compared with the ordinary type of kerosene engine the Semi- 
Diesel is much more positive in its action as the oil is sure to 
ignite when sprayed on the hot surface of the bulb or plate 
when under the comparatively high compression. In the engine 
where the air is mixed with the vaporized fuel before it is drawn 
into the cylinder, it is difficult to obtain perfect combustion be- 
cause of the uncertain mixtures obtained on varying loads by 
the throttling method of governing. At light loads the only 
difficulty encountered with the Semi-Diesel type is that of 
keeping the igniting surface hot enough to fire all of the 
charges. 

In the majority of cases the two stroke cycle type of Semi- 
Diesel engines compress the scavenging air in the crank cham- 
ber in the same way that a two stroke cycle gasoline motor 
performs the initial compression, although there are several 
makes that compress the air in an enlarged portion of the cyl- 
inder bore by what is known as a "trunk" piston. This initial 
compression determines the speed of the engine, the pressure 
limiting the time in which the air traverses the cylinder bore 
and sweeps out the burnt gases of the previous explosion. 

(68) De La Vergne Oil Engines. 

Two types of four stroke cycle oil engines are built by the 
De La Vergne Machine Company, which differ principally in 
the method and period of injecting the fuel into the cylinder. 
While both types compress only pure air in the working cylin- 
der, the oil is injected in a heated vaporizer during the suction 
stroke in the smaller engine (type HA), and is injected directly 
into the combustion chamber of the larger engine (type FH) 
at the point of greatest compression. This fuel timing classi- 




-'-'■ 



GAS, OIL AND STEAM ENGINES 



179 



fies the type FH as a semi-Diesel, while type HA comes under 
the head of that class of engines known as aspirators. 

Semi-Diesel (Type FH) 

During the suction stroke, air is drawn into the cylinder 
through the inlet valve located on the top of the cylinder head, 
and on the return, or compression stroke, the air is compressed 




76-b. Cross-Section of Type F H, De La Vergne Oil Engine. 

to about 300 pounds per square inch in the combustion cham- 
ber. The compression heats the air to a high temperature 
which is still further increased by contact with the hot walls 
of a cast iron vaporizer D, shown by Fig. 76-b. At the com- 
pletion of the compression, the fuel is injected in a highly 
atomized state by compressed air through the spray nozzle F, 
the spray being thrown into the vaporizer. 

The vapor formed by the contact of the spray with the walls 



180 GAS, OIL AND STEAM ENGINES 

of the vaporizer mixes with the compressed air in the com- 
bustion chamber and is ignited at the instant of fuel admission 
by the combined temperatures of the vaporizer and compres- 
sion pressure. 

As the fuel is not injected until the proper instant for igni- 
tion, it is possible to obtain a relatively high compression 
without danger of the charge preigniting. The oil is supplied 
to the nozzle by a fuel pump under pressure. The atomizing 
air takes the oil at pump pressure and performs the actual 
injection. Details of the spray valve are shown by Fig. 76, 
in which the oil and air are entered at a pressure of about 
600 pounds per square inch. 





Fig. 76. De La Vergne Spray Nozzle. 

The air and oil enter the nozzle at opposite sides of the 
cylinder B which fits snugly into the valve body A. As the 
air and oil proceed side by side along the outside of B, they 
are forced to pass through a series of chambers connected 
by a system of fine diagonal channels on the surface of B 
which results in a very fine subdivision and intimate mixture. 
The charge is admitted to the cylinder by a sort of needle 
valve about one-half inch in diameter which is provided with 
a spring that holds it closed on its seat as shown by C, in 
Fig. 76. The needle is so constructed that it may be readily 
removed at any time for inspection. The spray valve is located 
on the right hand side of the valve chamber directly opposite 



GAS, OIL AND STEAM ENGINES 



181 



the vaporizer and is operated by an independent cam on the 
camshaft. 

The vaporizer consists of an iron thimble having ribs 
on the inside to increase the radiating surface. In start- 




Fig. 76-c. De La Vergne Governor and Fuel Pump. 

ing, the vaporizer is heated for a few moments until it reaches 
the temperature necessary for vaporizing the fuel, but after 
the engine is running, the blast lamp is removed and the tem- 
perature is maintained by the heat generated by the com- 



182 GAS, OIL AND STEAM ENGINES 

bustion of the successive charges. Since the fuel is ignited 
at the instant that it makes contact with the vaporizer, it is 
possible to accurately adjust the point of ignition by adjusting 
the position of the fuel cam on the camshaft. 

Air for spraying the fuel is supplied by a two stage air 
compressor that is driven from the crankshaft by an eccen- 
tric. The air compressed by the first stage is stored in tanks 
at about 150 pounds pressure for starting the engine. The 
second stage compresses the air to about 600 pounds pressure, 
but is correspondingly small in volumetric capacity since it 
handles only enough air to spray the oil which amounts to 
about 2 per cent of the cylinder volume. A governor con- 
trolled butterfly valve in the air intake pipe regulates the 
amount of air taken in on the second stage to suit the vary- 
ing charges of oil injected at each load. 

In starting by compressed air, a quick opening lever oper- 
ated valve on the cylinder head is used to admit air from the 
tanks to turn the engine over until the first explosion takes 
place. If the vaporizer is sufficiently heated by the torch, 
the explosion occurs during the first revolution of the crank 
shaft. At a point about 85 per cent of the expansion stroke, 
the exhaust valve is opened, and the products of combustion 
are expelled into the atmosphere. When starting, the com- 
pression may be relieved by shifting the starting lever from 
the exhaust cam to the auxiliary starting cam provided for 
that purpose. 

Speed regulation is affected by a Hartung governor, driven 
from the camshaft, which actuates the oil supply pump 
through levers by shifting the point of contact between the 
pump levers and its actuating cam. This lengthens or shortens 
the stroke of "the pump in accordance with the requirements 
of the load. The type FH engines are built in both single 
and twin cylinders ranging from 90 to 180 horse-power in 
the single cylinder type to 360 horse-power in the twin. 

Since the fuel injection of the smaller engine type HA differs 
from that just described, it will be described separately in 
the following section. 

The De La Vergne Oil Engine (Type HA) 

In the small four stroke cycle De La Vergne Oil Engine, 

the fuel is injected into a heated vaporizer during the suction 

stroke in such a way that the vapor and intake air do not form 

a mixture in the cylinder proper. On the return stroke of 



GAS, OIL AND STEAM ENGINES 183 

the piston, the compression of the pure air takes place which 
forces the air into the vaporizer and into intimate contact 
with the oil vapor. This forms an explosive mixture which 
ignites and forces the piston outwardly on the working stroke. 
The release and scavenging are performed in a similar man- 
ner to that of a four stroke cycle gas engine. Both the inlet 
and exhaust valves are of the mechanically operated poppet 
type, and as both the inlet and exhaust gases pass through 
the same passage, the entering air i* heated to a comparatively 
high temperature. 

The injection pump receives the fuel from a constant level 
stand pipe or tank, located near the engine and injects the 
fuel into the vaporizer through a spray nozzle. The vaporizer 
is a bulb shaped vessel that is connected with the cylinder 
through a short post and really forms a part of the combus- 
tion chamber. Since no water jacket surrounds the vaporizer, 
it remains at a high temperature and vaporizes the oil at the 
instant of its injection. Because of the residual gases remain- 
ing in the chamber, ignition does not occur until air is forced 
through the passage by the compression. The air inlet valve 
and the fuel injection valve are opened at the same instant by 
a cam lever that also operates the pump. 

On the compression stroke, the air which is at a pressure 
of approximately 75 pounds per square inch enters the vapor- 
izer, and ignition occurs, partly because of the increased heat 
due to the compression and partly because of the supply of 
additional oxygen. Internal ribs provided in the vaporizer 
greatly increase the heat radiating surface and add to the 
thoroughness with which the atomized oil is vaporized. Since 
no mixture of air and fuel takes place in the cylinder proper, 
sudden changes in the load do not affect the ignition of the 
charge as the heated surfaces are surrounded with compara- 
tively rich gas under all conditions. 

Before the engine is started, the vaporizing chamber is heated 
to a dull red heat by means of a blast torch in order to vaporize 
the oil for the first stroke. As soon as the engine is running, 
the lamp is cut out and the temperature is maintained by 
the heat of the successive explosions. The combustion at- 
tained by this method is very complete even with the heaviest 
fuels, and whatever carbon deposit is formed occurs in the 
vaporizer from which it is easily removed. The contracted 
opening of the vaporizer passage effectually prevents the solid 
matter from working in the bore or valves. 



184 GAS, OIL AND STEAM ENGINES 

A Porter-type fly ball governor maintains a constant speed 
at varying loads by regulating the quantity of fuel supply to 
the vaporizer, the air intake remaining constant. A by-pass 
valve, controlled by the governor divides the oil supplied by 
the pump, into two branches, one of which leads to the 
spray nozzle and the other to the supply tank. In the case 
where all of the oil is not supplied to the vaporizer because 
of a light load, the by-pass valve will return the surplus to 
the tank, thus maintaining a constant pressure at the spray 
nozzle. 

When operating under ordinary loads, the governor opens 
only the small inside valve which regulates the amount of oil 
injected into the vaporizer. But should the engine speed up, 
due to a sudden change in the load, the governor will not 
only open the small valve but also the large concentric valve, 
in which case all of the oil will return to the tank. The mak- 
ers guarantee the following speed variation limits under the 
different loads. 

Ordinary Variation 2y 2 per cent. 

Full load to one-quarter load 4 per cent. 

Full load to no load 5 per cent. 

(69) Operating Costs of the Semi-Diesel Type. 

As the semi-Diesel type engine will operate successfully on 
the lowest grades of crude oils, with an efficiency that compares 
favorably with the true Diesel type, the operating expenses are 
very much lower than with the gas or gasoline engine. With 
the same fuels, the semi-Diesel will show greater net saving 
than the Diesel with a low load factor, as the fuel saving is 
not eaten up by the high first cost, and overhead charges of 
the true Diesel. Western crude oils with a specific gravity of 
.960 (16° Beaume) are being used daily with this type of en- 
gine while nearly every builder of the semi-Diesel type will 
guarantee results with oils up to 18° Beaume (.948 Specific 
Gravity). Fuel of this grade will cost anywhere from \y 2 cents 
to 2>y 2 cents per gallon in tank car lots, depending on the dis- 
tance of the engine from the wells or refinery. 

With fuel oil weighing 7y 2 pounds per gallon, an engine 
consuming .65 pounds per horse-power hour (a usual guarantee) 
at full load, the cost of a horse-power hour delivered at the 
shaft will be .26 cent with fuel at 3 cents per gallon. This 
the lowest fuel expense of any prime mover even with steam or 
gas units of great power. In a twenty-four hour test of a 



GAS, OIL AND STEAM ENGINES 185 

De La Vcrgne oil engine running on 19° Beaume oil, the con- 
sumption was considerably below the figure assumed above, 
being .508 pounds per horse-power hour. Even the engine 
was exceeded in. a test made on a 175 horse-power engine 
by Dr. Waldo, which gave a consumption of .347 pounds of oil 
per horse-power hour with oil of .86 Specific Gravity. 

The following is a tabulation of reports received by the 
De La Vergne Machine Company from the Snead Iron Works, 
giving the cost of power at their plant under actual working 
conditions extending over a period of twenty-four months. 
The plant consisted of a 17 X 2iy 2 inch De La Vergne semi- 
Diesel type engine of 180 horse-power rated capacity, the 
load factor being 54.2 per cent. The total power produced 
during the record was 552,217 horse-power hours, with a work- 
ing period of 588 days. Fuel = 28.8° Beaume = 7.35 pounds 
per gallon. 

TABULATION 

Items Total Cost Cost per Cost per 

K.W. Hour H. P. Hour 

Fuel Oil, 38,211 gallons $859.75 $.00232 $.00155 

Lubricating Oil 228.72 .00061 .00041 

Miscellaneous Stores and Repairs... 123.20 .00032 .00022 

Labor and Attendance 1361.42 .00368 .00246 

Total $.00693 $.00464 

Fuel oil used = .761 pounds per K. W. hour = .508 pounds 
per horse-power hour. Computing from the load factor of 
54.2 per cent, the cost of power produced under the above 
conditions would be $9.30 per horse-power year, or $13.98 per 
kilowatt year. This result is obtained by assuming that the 
horse-power hours would be increased from 552,217 to 1,077,354, 
or in proportion to the actual load factor, the period, of course 
being the same in both cases. 

(70) Elyria Semi-Diesel Type. 

A type of semi-Diesel type oil engine has been recently 
developed by the Elyria Gas Power Co., Elyria, O., that 
presents many features of interest. It operates on the two 
stroke cycle principle, and with the exception of the spray 
nozzle has no valves in the working cylinder. The prin- 
ciple of the semi-Diesel type cycle as distinguished from the 
true Diesel engine, was described in Chapter III, as having 



186 GAS, OIL AND STEAM ENGINES 

the following characteristics. (1) Fuel injection. (2) Medium 
compression pressure. (3) Hot plate ignition. (4) An ef- 
ficiency approximating that of the true Diesel type. 

It is claimed that the change from the ordinary four stroke 
cycle Diesel cycle has been accomplished with practically no 
loss of thermal efficiency, and that the elimination of the many 
moving parts of that type has done away with many of the 
operating difficulties. By the introduction of a false piston 
end and an unjacketed cylinder head, the loss of efficiency due 
to the lower compression is compensated by the reduction of 




Fig. 77. Working Cylinder of Elyria Oil Engine. 

heat loss to the jacket water. Because of the high temper- 
ature it is possible to burn the heaviest fuels with a maximum 
pressure not exceeding 400 pounds per square inch, and with- 
out trouble due to missed ignition at light loads. With a given 
cylinder capacity this heating effect has increased the output 
about 75 per cent. The loss due to the friction of the scaveng- 
ing apparatus causes a fuel consumption of approximately 10 
percent more than a standard four stroke Diesel. 

Unlike the Diesel, this engine automatically controls the 
quantity of injection air admitted to the cylinder at different 
loads, the air corresponding with the amount of fuel injected. 
This is in marked contrast with the Diesel engine which admits 
a constant volume of air at all loads. In place of the usual 



GAS, OIL AND STEAM ENGINES 



187 



crank-case compression of the scavenging air met with in the 
ordinary two stroke cycle engine, the initial compression in 
the Elyria engine is performed by a "differential piston" which 
acts in an enlarged portion of the cylinder bore. This con- 
struction increases the volumetric efficiency from 70 percent, 
in the case of the marine type, to well over 90 percent, and it 
also does away with the bad effect of the compression on the 
lubrication of the main crank shaft bearings. 

The working piston and differential piston as shown by Fig. 
77 is separate castings fastened together by four studs, and the 




Fig. 78. Compressor Cylinder of Elyria Oil Engine. 



piston pin is carried by the differential piston which acts as a 
cross-head, taking all of the side thrust from the main piston. 
The working piston is easily taken from the cylinder by remov- 
ing the cylinder head and the four nuts that fasten it to the 
differential piston casting. The displacement of the differential 
piston is approximately 1.9 times the displacement of the work 
ing piston which is more than enough for thoroughly scaveng 
ing the cylinder and supplying air for combustion. The air 
suction is controlled by a piston valve which eliminates much 
of the loss encountered in the marine type of two stroke cycle. 
In the figure may be seen the separate or auxiliary piston 
head which is bolted to the piston proper, a construction that 
greatly increases the working temperature, and allows a sym- 
metrical form of piston. By removing the cap over the inlet 



188 GAS, OIL AND STEAM ENGINES 

port, it is possible to inspect the condition of the six piston 
rings with removing the piston from the cylinder. Because of 
the clean burning of the fuel lubrication is easily effected by 
the force pump which supplies oil at three points around the 
cylinder wall. 

Three stages of compression are employed for providing the 
air for fuel injection, the first stage being accomplished by the 
differential piston, and the remaining two stages by a separate 
air pump driven by an eccentric from the crankshaft. This 
cylinder also supplies the air for starting the engine, the air 
being taken from the second stage and piped to the storage 
tank. The suction of the second stage pump which receives its 
air from the differential pump (first stage) is controlled auto- 
matically so that it is possible to keep the supply tank at any 
desired pressure regardless of the pressure or amount of air 
used for the fuel injection. Air from the tank (at approximately 
200 pounds pressure) is piped to the suction side of the third 
stage air pump. In this suction line is a valve, controlled by 
the governor, which regulates the amount of air admitted to 
the injection nozzle, and also the amount. This pressure at 
the nozzle will vary from 500 pounds per square inch to 1000 
pounds depending on the load and the nature of the fuel. The 
high pressure air travels directly from the pump to the fuel 
valve casing, and is equipped with a safety valve and pressure 
gauge. 

The fuel pump is driven by a Rites Inertia Governor located 
in the fly-wheel which varies the stroke of the pump plunger 
and gives a correct proportion of fuel to the load. This type 
of governor has been extensively used on high speed engines 
and is exceeding accurate. The fuel pump may be disconnected 
from the governor drive, and operated by hand when it is nec- 
essary to provide fuel for starting. The spray or injection valve 
is operated by a cam, which lifts the valve at the proper mo- 
ment in a very simple manner. The valve proper is made of 
a single piece of steel with openings of ample size, so that 
there is no danger of clogging with the heaviest fuels. As the 
valve only lifts 1/16 of an inch, the amount of work required 
to operate the valve is very small. 

Starting is accomplished by spraying cold gasoline into the 
cylinder through the fuel valve in the same manner that the 
heavier oil is fed during operation, and the ignition is performed 
by a high tension coil and batteries. No spark time device is 
used, so that a continuous shower of sparks is thrown into 



GAS, OIL AND STEAM ENGINES 189 

the mixture during the starting period. Within a minute after 
the engine is started, the ignition switch may be opened, the 
gasoline cut off, and the heavy oil turned on for continuous 
running on full load. Starting by an electric spark avoids the 
inconvenience and danger of torch starting with a retort. 

Cooling water is admitted around the compressor cylinder 
from which point it goes to the working cylinder, and is 
there discharged. Less water is required for this type of engine 
than for the ordinary gasoline engine, for with the water en- 
tering at 60°F, only 3 gallons per horse-power hour is used. 
With fuel oil weighing 7.33 pounds per gallon the makers 
claim a fuel consumption of .65 pounds per horse-power at the 
rated load. The amount of cylinder oil used does not exceed 1 
pint per 100 horse-power hours, while the loss of the bearing 
oil is extremely small because of the return system. 

(71) Remington Oil Engine. 

The Remington Oil Engine is a vertical oil engine operating 
on the three port, two stroke cycle, and is an oil engine in the 
strict meaning of the word, the oil consumed being introduced 
into the combustion chamber as a liquid and gasified within this 
chamber. 

The method of gasifying and igniting the charge of oil in 
the Remington Oil Engine is unique. Only clean air un- 
mixed with any charge, is taken into the crankcase. This air 
is afterwards passed up into the cylinder and compressed until 
its temperature has raised to a point high enough to vaporize 
the oil which is injected into it. The charge of oil is then 
atomized into this hot compressed air and turns immediately 
into a vapor, which finds itself well mixed with the charge of 
air, comes in contact with a firing pin recessed in the head, 
ignite and burns. This method of having the oil well gasified 
and mixed with air before ignition begins, prevents the forma- 
tion of carbon which is formed when oil not well gasified and 
mixed with air comes suddenly i.n contact with very hot 
surfaces. 

This perfect system of gasifying the oil has the effect not 
only of preventing the formation of carbon in the cylinder, but 
also of increasing the mean effective pressure and therefore de- 
creasing the amount of fuel necessary for doing a certain 
amount of work. The engine passes through its cycle of oper- 
ations smoothly, and does not have to be constructed with ex- 
cessive weight. 



190 GAS, OIL AND STEAM ENGINES 




Fig. 79. Cross-Section of Remington Oil Engine. 



GAS, OIL AND STEAM ENGINES 191 

The Remington Engine is of the valveless type, delivering a 
power impulse in each cylinder for each revolution of flywheel. 
The gases are moved in and out of the cylinder through ports 
uncovered by the movement of the piston, which itself performs 
also the function of a pump. 

On the up stroke of the piston a partial vacuum is created 
in the enclosed crankcase, causing air to rush in when the bot- 
tom of the piston uncovers the inlet port seen directly under 
the exhaust port (23), Fig. 79. On the next down stroke this 
air is compressed in the crankcase to about four or five pounds 
pressure per square inch. Meanwhile the mixture of oil vapor 
and air already in the cylinder is burning and expanding. 
When the piston approaches the end of its down stroke, it 
uncovers the exhaust port (23), permitting the burnt charge 
to escape, until its pressure reaches that of the atmosphere. 




Fig. 80. Remington Spray Nozzle. 

Directly afterward the transfer port on the opposite side of 
the cylinder is uncovered by the piston, thereby allowing a 
portion of the air compressed in the crankcase to rush into 
the cylinder, where it is deflected upwards by the shape of the 
top of the piston and caused to fill the cylinder, thereby expell- 
ing the remainder of the burnt charge. The piston now starts 
upward, compressing the fresh charge of air into the hot 
cylinder head. Near the end of the stroke, a small oil pump, 
mounted on the crankcase and controlled by the governor, in- 
jects the proper amount of oil through the nozzle (13), into 
the compressed and heated air. 

This oil is atomized in a vertical direction through a hole 
near the end of the nozzle. It is therefore vaporized and gasi- 
fied before there is a possibility of its reaching the cylinder 
walls. 

The spray of oil is ignited by the nickel steel plug (12), 
which is kept red hot by the explosions because the iron walls 
surrounding it are protected from radiation by the hood (11). 



192 



GAS, OIL AND STEAM ENGINES 



By the burning of the oil spray in the air the pressure is grad- 
ually increased and the piston forced downward, this being the 
power or impulse stroke. Near the end of the down stroke, 
the exhaust port is again uncovered and the burnt gases dis- 
charged. 




Fig. 81. Fuel Pump and Mechanism of Remington Oil Engine. 

The operations above described take place in the cylinder 
and crankcase with every revolution. Each upstroke of the 
piston draws fresh air into the crankcase and compresses the 
air transferred to the cylinder. Each down stroke is a power 
stroke, and at the same time compresses the air in the crank- 
case preparatory to transferring it to the cylinder by its own 
pressure at the end of the stroke. 

The same volume of air enters the cylinder under all condi- 
tions, and the power is regulated by modifying the stroke of the 



GAS, OIL AND STEAM ENGINES 



193 



oil pump, which may be done by hand or automatically by the 
governor in the flywheel. A separate fuel pump is provided 
for each cylinder when multiple cylinders are used, making it 
absolutely certain that each cylinder shall receive the same 
amount of fuel for a position of the control lever. 

When starting the engine, the hollow cast iron prong rising 
from the cylinder head is heated by a kerosene torch, and when 
hot, a single charge of oil is admitted to the cylinder by work- 
ing the hand pump. The flywheel is now turned backward, 
thereby compressing the charge which ignites the fuel before 
the piston reaches the highest position. After being started 
the engine, the torch may be extinguished. 




Fig. 82. Two Cylinder Remington Oil Engine Direct Connected to 

Dynamo. 

The governor is of the centrifugal type. It has an L-shaped 
weight, pivoted to the piece attached to the flywheel. As the 
engine speed increases, the weight tends to swing outward 
toward the flywheel rim, and thereby moves the arm attached to 
it so as to shift the cam along the crankshaft toward the left. 

This cam turns with the shaft, and operates the kerosene 
oil pump. According to the position of the cam on the shaft, 
it will impart to the pump plunger a long or a short stroke, 
thereby injecting more or less oil into the cylinder. The lever 
pivoted on the bracket moves with the cam and is used for 



194 GAS, OIL AND STEAM ENGINES 

controlling the engine's speed by hand. To stop the engine 
the handle of the lever is pulled towards the flywheel, thereby 
interrupting the pump action altogether. 

The handle of the control lever can be fitted with an ad- 
justable speed regulator when required. This device is for 
use on marine engines to enable the operator to slow down 
the engine. The speed regulator does not interfere with the 
action of the governor but acts in conjunction with it. What- 
ever the speed of the engine may be, it is under the control of 
the governor. The engine can be controlled from the pilot 
house if such an arrangement is desirable. . 

The fuel pump is made of bronze. The valves are made 
of bronze and are designed with very large areas. The plunger 
is made of tool steel. A bronze cup strainer is attached to the 
lower end of the pump to prevent sediment or foreign matter 
from reaching the pump valves. As a result of the care used 
in its construction, the fuel pump is not only very sensitive in 
measuring the oil required by the governor, but is also very 
strong and durable. 

The nozzle through which the fuel is atomized into the 
cylinder is thoroughly water jacketed to prevent the forma- 
tion of carbon within the nozzle. It is so constructed that the 
water jacket spaces and fuel spaces can be opened for inspection. 

Lubrication of all the important bearing joints is effected by 
a mechanical force feed oiler, pressure feed oiler or by gravity 
sight feed oilers, depending upon the service for which the en- 
gine is designed. Oil is fed in this manner to the piston, the 
main bearings and the crankpin bearings. The oil for the 
crankpin is dropped from a tube into an internally flanged ring 
attached to the crank by which it is carried by centrifugal force 
to a hole drilled diagonally through the crank and crankpin to 
the centre of the bearing. This insures that all the oil intended 
for the crankpin shall reach it. This feature, as well as the 
use. of the sight feed oiler itself, is in line with the best modern 
high speed engine practice, and is an important factor in the 
reliability of the engine. 



CHAPTER VIII 
IGNITION SYSTEMS 
(73) Principles of Ignition. 

It is the purpose of the ignition system to raise a small 
portion of the mixture to the combustion temperature, or the 
temperature at which the air and fuel will start to enter into 
chemical combination. When combustion is once started in 
a compressed combustible gas it will spread throughout the 
mass no matter how small the original portion inflamed. The 
rate at which the flame spreads through the combustion cham- 
ber depends upon the compression pressure, the richness of 
the mixture, the nature of the fuel and upon the number of 
points at which it is ignited. 

In practice perfect ignition is seldom realized. This is due 
not only to the ignition system itself but to poor mixture 
proportions, imperfect vaporizing of the fuel, and low com- 
pression; all of which tend to a slow burning mixture with the 
attendant losses. 

The best ignition system w T ill be that which will cause the 
ignition to occur invariably at the point of highest compres- 
sion and which will supply ample heat to start the process of 
combustion with a cold cylinder, imperfect mixtures, and low 
compressions. An efficient and reliable ignition system is with- 
out a doubt the most important unit in the construction of a 
gas engine. As ignition systems have improved and become 
more reliable, so has the gas engine become more widely used 
and appreciated, and in almost a direct proportion to these im- 
provements. 

Many ingenious ignition systems have been proposed, but 
only two of these have met with any degree of success in 
practice; i. e., electrical ignition and ignition by means of the 
hot tube. 

Sponge platinum has the peculiar ^property of igniting jets 
of hydrogen gas, or hydrocarbons, without the aid of heat; 
this is due to the condensing effect of the platinum on these 
gases. 

195 



196 GAS, OIL AND STEAM ENGINES 

It was proposed to ignite the gaseous charge of the gas en- 
gine by means of the platinum sponge (catalytic ignition) but 
the system proved a failure because of the clogging of the 
pores in the sponge by fine particles of soot. 

Dr. Otto employed an open flame which was introduced into 
the mixture by means of a slide valve. This met with only a 
fair measure of success. 

Cerium, Lanthum and several other rare metals cause a 
considerable spark when brought into contact with iron or 
steel. The objection to this method was the expense of the 
Cerium plugs which required frequent renewal. 

The writer remembers a quaint attempt at firing the charge 
by means of a piece of flint and steel; the failure of this is 
obvious. 

The Diesel Engine, a great success from a thermodynamic 
standpoint, is fired by means of the heat produced by the com- 
pression of air, the fuel being sprayed into air which is com- 
pressed to several hundred pounds pressure. 

Mr. Victor Lougheed proposes ignition by means of a plati- 
num wire rendered incandescent by a current of electricity. 
The plan sounds feasible, but we are still waiting to be shown. 

Electric ignition is applicable to all classes of engines; in 
fact this system made the variable speed engine as used on 
automobiles, etc., a possibility, as accurate timing with the 
electric spark covers the range from the lowest possible speed 
to speeds of 4,500 revolutions per minute and over. 

(74) Advance and Retard. 

While the combustion of the mixture is extremely rapid 
under favorable conditions, there is, nevertheless, a percep- 
tible lapse between the instant of ignition and the final pres- 
sure established by the heat of the combustion. For this rea- 
son it is necessary that ignition should be started a certain 
length of time before the pressure is required if we are to ex- 
pect a maximum pressure at a definite point in the stroke of 
the piston. The amount by which the time of ignition precedes 
that of combustion is called the ADVANCE, and is usually 
given in terms of angular degrees made by the crank in travel- 
ing from the time of ignition to time of maximum pressure. 
Since the pressure is always required at the extreme end of 
the compression stroke, the degree of advance is given as 
the angle made by the center line of the cylinder with the center 
line of the crank at the instant of ignition. Should the ad- 



GAS, OIL AND STEAM ENGINES 197 

vance be given as 10°, for example, it is meant that the crank 
is still 10° from completing the compression when ignition 
occurs. 

Owing to variations in the richness of the mixture, and 
changes in the compression pressure, due to throttling the 
incoming charge, the rate of inflammation varies from time to 
time under varying loads. To keep the maximum pressure at 
a given point under these conditions it is necessary to vary 
the point of ignition to correspond with the increase or de- 
crease of inflammation. This variation of advance to meet 
varying loads is approximated by the governor in some engines, 
and manually in others. The advance of an automobile is an 
example of manual ignition control. Should the point of igni- 
tion vary from the theoretical point it will result in a loss of 
fuel and power, and for this reason the ignition should be 
under at least an approximate control. A wide variation in 
engine speed has a very considerable effect on the ignition 
point as there is less time in which to burn the mixture at 
high piston speeds, and consequently the ignition must be 
further advanced to insure complete combustion at the end of 
the stroke. This fact is evident to those who have driven auto- 
mobiles. 

Should the ignition occur too early, so that combustion is 
complete before the piston reaches the end of the stroke, there 
will be a loss of power due to the tendency of the pressure to 
reverse the rotation of the engine. When starting an engine, 
over-advanced ignition will throw the crank over in the 
reverse direction from which it is intended to go, and will not 
only prevent the engine from coming up to speed but will prove 
dangerous to the operator. 

Due to the effects of inertia and self induction in several 
types of ignition apparatus, a greater advance will be required 
than that demanded by the combustion rate of the mixture. 
This sluggishness of the apparatus in responding to the piston 
position is called ignition LAG. The total advance required 
to have the combustion complete at the end of the stroke is 
equal to the advance required by the burning speed plus the 
ignition lag. Since lag is principally due to inertia effects, 
it is much greater at high speeds than at low, and it therefore 
causes an additional advance at high speeds. Causing the igni- 
tion to occur before the crank reaches the upper dead center 
is called ADVANCED IGNITION, causing it to occur after 
the piston has reached the upper dead center, or when on the 
outward stroke, is called RETARDED IGNITION. 



198 GAS, OIL AND STEAM ENGINES 

Ignition is retarded when starting an engine to prevent it 
from taking its initial turn in the wrong direction. As the 
combustion takes place after the compression, with the piston 
moving on the working stroke, in retard, it is impossible for 
the pressure to force the piston in any direction but the right 
one. Excessively retarded ignition will cause a power l<5ss and 
will also cause overheating of the cylinder and valves as the 
combustion is slower. 

(75) Preignition. 

Preignition which is in effect the same as over-advanced 
ignition as due to causes within the cylinder such as incandes- 
cent carbon deposits or thin sharp edges in the cylinder that 
have become incandescent through the heat of the successive 
explosions., Preignition is very objectionable since it causes 
heavy strains on the engine parts and causes a loss of power 
in the same way as over-advanced ignition. Any condition 
that causes the preigniting of the charge should be removed 
immediately. 

(76) Misfiring. 

The failure of the ignition apparatus to ignite every charge 
is called MISFIRING. This missing not only causes a waste 
of fuel and a loss of power but it also causes an increased strain 
on the engine parts because of the violence of the explosion 
following the missed stroke. The heavy explosion is due to the 
fact that the stroke following the "miss" is more thoroughly 
scavenged by the two admissions of the mixture than the or- 
dinary working stroke, and consequently contains a more active 
charge. 

(77) Hot Tube Ignition. 

A combustible gas may be ignited by bringing it into contact 
with surface heated to, or above the ignition temperature. It is 
upon this principle that hot tube ignition is based. 

In practice this surface is provided by the bore of a tube 
which is in communication with the charge in the cylinder, the 
outer end of the tube being closed or stopped up. Around this 
tube is an asbestos-lined chimney which causes the flame from 
the Bunsen burner to come into contact with the tube and also 
prevents draughts of air from chilling it. 

A Bunsen burner is located near the base of the tube and 
maintains it at bright red heat. The gas for the burner is sup- 



GAS, OIL AND STEAM ENGINES 199 

plied from a source external to the engine. When the fuel 
used is gasoline, a gasoline burner is used, which is fed from 
a small supply tank located five or six feet above the burner. 

During the admission stroke, the hot tube is filled with the 
non-combustible gases remaining from the previous explosion, 
therefore/ the fresh entering gases cannot come into contact 
with the hot walls of the tube and cause a premature explo- 
sion, before the charge is compressed. 

As the compression of the new charge proceeds, the fresh 
gas is forced farther and farther into the tube and at the 
highest point of compression it has penetrated far enough to 
come into contact with the hot portion. At this point the 
explosion occurs. 

The tube being of small bore, does not allow of the burnt 
gases mingling with the fresh within the tube; the waste gases 
in the tube acting as a regulating cushion. The distance of 
travel of the new mixture is proportional to the compression, 
hence the explosion does not occur until a certain degree of 
compression is attained. 

The length of the tube required for a given engine is a mat- 
ter of experiment, as is also the location of the heated portion. 
High compression naturally forces the mixture farther into 
the tube than low, therefore the flame should come into con- 
tact with the tube at a point nearer the outer end with high 
compression than with a low compression. 

Shortening the tube causes advanced ignition, as the mixture 
reaches the heated portion sooner, or earlier in the stroke, 
because of the decreased cushioning effect of the residue gases 
in the tube. 

The length of tube and location of maximum heat zone 
should be so proportioned that combustion will take place at 
the highest compression. Moving flame to outer end of the 
tube retards ignition. Moving the flame toward the cylinder 
advances it. 

While the hot tube is the acme of simplicity in construction, 
it is not the easiest thing to properly adjust, as the adjustment 
depends on compression, temperature of the tube, and the 
quality of the mixture. Any of these variables may cause im- 
proper firing. 

The hot tube is rather an expensive type of ignition with 
high priced fuel, as the burner consumes a considerable amount 
of gas, and is burning continuously during the idle strokes as 
well as during the time of firing. 



200 GAS, OIL AND STEAM ENGINES 

It is practically impossible to obtain satisfactory results from 
a hot tube on an engine that regulates its speed by varying the 
mixture or compression, as engines running on a light load 
will not have sufficient compression to cause the mixture to 
come into contact with the hot surface, the engine misfiring 
on light loads. 

The tubes are made of porcelain, nickel steel alloy, or com- 
mon gas pipe, and are of various diameters and lengths. 

All of these materials have their faults. Porcelain being 
very brittle, is liable to breakage. Gas pipe burns out and 
corrodes rapidly. Nickel alloy is not liable to breakage, is not 
so susceptible to corrosion as iron, but is far from being a 
permanent fixture. 

Timing valves are a feature of some systems of hot tube 
ignition, which correct to a certain extent the irregularity of 
firing of the plain type of tube. 

The timing valve is introduced in the passage connecting the 
cylinder and tube, and prevents the gas in the cylinder from 
coming into contact with the heated surface until ignition is 
desired. 

The valve is operated by means of mechanism connecting it 
with the crank shaft. It is evident that with sufficient com- 
pression in the cylinder, the time of ignition can be obtained 
with certainty. 

This mechanism is rather complicated, and subject to wear, 
and the advantage gained by the fixed point of ignition is offset 
by mechanical complication and consequent trouble. 

The action of hot tube igniters is erratic and their use is not 
advisable unless under unusual conditions. The open flame used 
in heating the tube is a constant menace, as it is surrounded 
by inflammable vapors. This feature alone condemns it in the 
eyes of the insurance underwriters; in many places the use 
of the hot tube is prohibited both by the underwriters and 
city ordinances. 

The above inherent defects of hot tubes are supplemented 
by breakage, "blowing," and clogging of the tube or passage 
with soot and products of corrosion, each factor of which will 
cause misfiring. 

In case of misfiring, after determining that the tube is not 
broken or clogged with soot or dirt, see that the engine is 
being supplied with the proper mixture; that you are obtain- 
ing the proper compression; and that the Bunsen burner is de- 
livering a bright blue flame on the tube at the proper point, 



GAS, OIL AND STEAM ENGINES 201 

Never allow the burner to develop a yellow sooty flame. A 
yellow flame indicates that insufficient air is being admitted 
to the burner. Remember that an overheated tube is quickly 
destroyed, and will cause misfiring as surely as an underheated 
tube. Regulate the gas supply to the burner. 

A small leak near the outer end of the tube will destroy the 
cushioning effect of the burnt gas, and hence will cause pre- 
mature firing of the charge. Procure a new tube. 

Many engines are provided with a sliding burner and chim- 
ney which allows of some adjustment of the flame on the tube. 
In cases of persistent misfiring, move the chimney one way or 
the other. It may improve the ignition. 

(78) Electrical Ignition. 

Ignition by means of an electric spark is by far the most 
satisfactory method as it makes accurate timing and prompt 
starting possible. It is the most reliable of all systems and 
is easily inspected and adjusted by anyone having even a 
rudimentary idea of electricity or the gas engine. For this 
reason electric ignition is used on practically all modern en- 
gines (with the exception of the Diesel types). The spark is 
caused by the current jumping an opening or gap in the con- 
ducting path of the current, and the ignition of the charge 
is obtained by placing this cap in the midst of the combustible 
mixture to which the spark communicates its heat. 

The method of producing the spark gap, and the method 
by which the current is forced to jump the gap, divides the 
electrical ignition system into two principal classes: 

(1) The MAKE AND BREAK, or LOW TENSION system. 

(2) The JUMP SPARK or HIGH TENSION system. 

In either system the spark is produced by the electrical fric- 
tion of the current passing through the high resistance of the 
gas in the spark gap. The incandescent vapor in the gap 
formed by this increase of temperatures causes the flash that is 
known as the spark. The temperature of the gap depends 
principally upon the current flowing through it, the amount of 
heat developed being proportional to the square of the current. 

There is of course a practical limit to the amount of current 
used in the ignition apparatus to produce spark heat. The 
limit is generally set by considerations of the life of the bat- 
tery furnishing the current, expense of generating the cur- 
rent, and the life of the contact points between which the 
spark occurs. 



202 GAS, OIL AND STEAM ENGINES 

The heat developed by an electric current is proportional to 
the amount of resistance offered to its flow and the strength 
of the current employed. The greater the resistance, the more 
heat developed. 

The resistance of copper wire (the usual conducting path), 
being very low causes little rise in temperature, but the air in 
the opening or break has a resistance of many thousands of 
times the resistance of the copper; hence the current passing 
across the opening spark or gap raises the air to an exceed- 
ingly high temperature. 

With a comparatively heavy current flowing across the 
break, the temperature developed is high enough to boil or 
vaporize any metal in contact with the spark or flame, render- 
ing the metallic vapors incandescent. With sufficient current, the 
ends of the wires which constitute the break may be melted away. 

For the successful and continuous operation of the engine 
it is imperative that ends of the conducting path or terminals 
be made of a metal of a high fusing point in order to with- 
stand the heat of the spark and also that the current be 
kept to as low a value as possible. 

In actual construction the spark gap terminals are generally 
made of platinum or platino-iridium, or an alloy of high fuss- 
ing point. Iron is sometimes used, but deterioates rapidly. 
Nickel steel lasts longer than common iron or steel but is not 
as durable as platinum or its alloys. 

As the temperature of the electric spark or arc is approxi- 
mately 7,500° F., and the ignition temperature of an ordinary 
rich gas at 70 lbs. compression is 1,100° F., it is evident that the 
quantity of current for ignition may be kept to an exceedingly 
low value. High compression increases the resistance of the 
spark gap, and requires higher electrical pressure to force a 
given current across a gap of given length. 

(79) Sources of Current. 

The electric current that causes the ignition spark is usually 
generated or supplied by one of the three following methods: — 

1. By the primary battery which converts the chemical en- 
ergy of metal, and some corroding fluid, into electrical energy, 
by chemical means. 

2. By the magneto or dynamo that converts mechanical 
work or energy into electrical energy through the method 
of magnetic induction. 

3. By the storage or secondary battery which acts as a 



GAS, OIL AND STEAM ENGINES 203 

reservoir or storage tank for current that has been generated 
by either of the two above methods. A storage battery sim- 
ply returns electrical energy that has been expended on it by 
an external generator. A storage batteiy does not really gen- 
erate electricity but as it is often used as a source of current 
for an ignition system, we will consider it as a generator. 

Current producers that convert chemical or mechanical en- 
ergy into electrical energy are called primary generators, and 
are represented by the primary battery and dynamo. The 
above methods are used for generating current for either the 
high or low tension systems. 

Electricity may also be produced by friction, but as such 
current is without heat value it is not used for ignition pur- 
poses. Electricity produced by friction is called static electricity. 

Primary and storage batteries always deliver a direct or 
continuous current of electricity, that is a current which flows 
continually in one direction. Dynamos are usually made to 
furnish a direct current, but can be built to deliver either 
direct or alternating. 

Alternating current, unlike the continuous current, changes 
the direction of its flow periodically; flowing first in one direc- 
tion and then in the other, the flow alternating in equal periods 
of time. 

Magnetos being a special form of dynamo can furnish either 
class of current, but with few exceptions are built for generat- 
ing alternating current. 

Either current may be used for ignition purposes for either 
high or low tension systems. 

Alternating current has several advantages not possessed by 
the continuous current, when used for ignition purposes. The 
principal advantages are: 

1. Alternating current does not transfer the electrode metal 
of contact points, and consequently causes less trouble with 
vibrators and "make" and "break" ignitors. 

2. Magnetos generating alternating current are less com- 
plicated, have fewer parts to get out of order, and are cheaper 
to keep in repair. 

3. Alternating current is not liable to burn out spark coils 
or overheat with an excessive voltage. 

4. Alternating current generators can be used at any speed 
without the use of governors. 

When installing an ignition system give due consideration to 
the reliability of the source of current. The gas engine is no 



204 GAS, OIL AND STEAM ENGINES 




43-a. The Esselbe Rotary Aero Motor. Four Pistons are Contained 
in the Ring Shaped Cylinder at the Left Which are so Connected 
with Cranks and Gears in the Gear Box that the Pistons and the 
Cylinder Rotate in Opposite- Directions. As the Pistons Rotate 
they also Oscillate Back and Forth in Regard to One Another, so 
that the Working and Compression Strokes are Performed. From 
Aero London. 



GAS, OIL AND STEAM ENGINES 205 

more reliable than its source of current. Failure of the current 
means the failure of the engine. 

(80) Primary Batteries. 

Current is produced in a primary battery by the chemical 
action of a fluid known as an ELECTROLYTE upon two dis- 
similar metals or solids known as the electrodes. One of the 
electrodes, the negative, is usually made of zinc which is more 
readily attacked by the electrolyte than the positive electrode. 
As the metal of the negative electrode is dissolved and passes 
into the solution during the process of current generation, the 
electrolyte is also exhausted. The production of current is 
accompanied by the liberation of hydrogen gas from the elec- 
trolyte from which it is displaced by the zinc taken into solu- 
tion. 

When the electrodes are immersed in the electrolyte, and 
the outer ends of the electrodes are connected with a wire, a 
current will flow from the positive electrode to the negative 
through the wire, and from the negative to the positive elec- 
trode through the fluid. It will be seen that to complete the 
circuit between the electrodes it is necessary that the current 
flows through the electrolyte. 

Electrical energy is actually generated in the primary bat- 
tery by the chemical combustion of the negative electrode in 
the same way that heat energy is developed by the burning 
of a fuel. 

By connecting the binding posts of the electrodes to the 
two wires of the external circuit, a current will flow through 
the circuit as long as the electrodes remain undissolved, or 
until the positive electrode is covered with hydrogen gas 
bubbles. 

The bubbles of gas tend to insulate the positive electrode 
from the electrolyte or fluid, thus breaking the circuit through 
the fluid, and stopping the flow of current. This action is 
known as polarization. 

When a battery is polarized, the only remedy is to discon- 
nect it from the circuit and allow it to rest or recuperate. The 
greater the current drawn from a battery, the more rapid the 
polarization, and it is evident that if the battery is to be used 
for long periods, polarization must be eliminated, or the cur- 
rent must be considerably reduced in volume. A battery that 
delivers a small current has a much greater capacity in am- 
pere hours than a battery that has a higher rate of discharge. 



206 GAS, OIL s AND STEAM ENGINES 

The greater the discharge rate the longer must be the rest 
periods. 

A battery that is designed for continuous service, or for de- 
livering heavy currents of long duration, is called a closed- 
circuit battery. Polarization is eliminated in closed circuit 
batteries by various methods, the usual methods being to place 
some substance in the electrolyte that will destroy the hydrogen 
film; or by packing some solid oxidizing material around the 
positive electrode that will absorb the hydrogen; or by making 
the positive electrode of some material that will destroy the 
hydrogen as soon as it is developed. 

Batteries that are capable of being operated only for short 
periods, on account of polarization, are called open circuit 
batteries. Open circuit batteries are cheaper and more simple 
than closed circuit batteries. For ignition purposes, a battery 
is made that is a compromise between the closed and open 
circuit cells, this being a battery in which the polarization is 
only partially suppressed. As the demand for current on an 
ignition battery is small with comparatively long rests between 
contacts, the compromise battery answers the purpose and is 
fairly cheap. 

All prfmary batteries are in reality wet batteries, for the 
reason that it would be impossible to cause a chemical reac- 
tion and a current with a dry electrolyte. The action of dry 
and wet batteries is identical. 

There are many types of wet battery in use for various pur- 
poses, but few of them are adapted for gas engine ignition be- 
cause of a tendency to polarize or because of the cost of main- 
tenance. 

All wet batteries are not suitable for portable or automobile 
engines because of the slopping of the liquid electrolyte and the 
danger of breaking the containing jars. Their weight and bulk 
is also a drawback. 

If the electrolyte or the electrodes be made of impure ma- 
terial local currents will be generated. These currents de- 
crease the life of the cell without producing any useful current 
in the ignition circuit. Due to the deteriorating effects of the 
local currents, batteries standing idle for several months will 
often be found to be completely discharged and worthless 
without having done any useful work. In the better grade of 
cells this loss is reduced to a minimum. 

A type of wet battery using a solution of caustic soda for 
an electrolyte, and having zinc and copper oxide electrodes, is 



GAS, OIL AND STEAM ENGINES 207 

extensively used for stationary ignition purposes, and is the 
most satisfactory type of wet cell for continuous work with 
this class of engine. The caustic soda battery is of the 
CLOSED circuit type, and is capable of furnishing a strong 
uniform current without danger of polarization. 

The hydrogen bubbles which cause polarization are oxidized 
or eliminated by the copper oxide electrode as soon as they are. 
formed. The hydrogen combines with the oxygen of the cop- 
per oxide forming water. 

The copper oxide is gradually reduced to metallic copper by 
the reaction with the hydrogen, and in the course of time re- 
quires renewal. The copper oxide element is rather expensive 
and cannot be obtained as readily as the electrodes used in 
other cells. 

It will be noted that both electrodes are consumed in the 
caustic battery, the consumption of the zinc furnishing the 
current, and the reducing of the oxide furnishing the chemical 
energy for depolarizing the cell. 

(81) Dry Batteries. 

Dry batteries are by far, the most convenient and economical 
form of primary battery to use, for there is no fluid to slop 
and leak, the first cost is low, the output is large for the 
weight, and last but not least, the cell can be thrown away 
when exhausted without great monetary loss. This does away 
with the expense and annoyance of changing wet cells, a factor 
that will be appreciated by those that are far from a source 
of chemical supplies. Since the advent of the automobile the 
use of dry cells has extended so that they may be obtained 
in almost any country town or village. 

While the cell is not dry, strictly speaking, the solution is 
held in such a way that it cannot slop around in the cell nor 
leak out of the seal. The only fault of a dry cell is its ten- 
dency to deteriorate with age because of the constant contact 
of the electrolyte with the electrodes. 

The negative electrode of the dry cell (zinc) is in the form 
of a cup which serves as a containing vessel for the electro- 
lyte and the depolarizer. 

The electrolyte is usually composed of a solution of am- 
monium chloride, with a small percentage of zinc sulphate, this 
fluid being held by some absorbent material such as blotting 
paper, or paper pulp. 

The electrolyte is applied to the electrodes by means of the 



208 GAS, OIL AND STEAM ENGINES 

saturated blotting paper, which is also used to line the zinc 
container, thus providing insulation between the electrodes. 

A rod of solid carbon which forms the positive electrode is 
placed in the center of the container, and the space between 
the rod and the zinc is packed solidly with granulated carbon, 
the blotting paper lining preventing contact of the zinc with 
the carbon. 

Pulverized manganese dioxide is mixed with the granulated 
carbon for a depolarizer. 

After the zinc container is filled with the electrolyte and 
pulverized carbon, the top of the container is closed hermetic- 




Brookes Four Cylinder Gasoline Engine Direct Connected to Dynamo. 



ally by means of sealing wax. Granulated carbon is used for 
it presents a large surface to the electrolyte, reduces the 
internal resistance of the cell, and therefore increases the cur- 
rent output of the battery. 

As soon as the battery starts generating current, polarization 
begins, with the liberation of hydrogen gas. If the cell is 
discharged at a high rate, the manganese dioxide will be un- 
able to absorb all of the gas, and consequently pressure will 
be erected within the cell. The greater the rate of discharge, 
the greater will be the amount of hydrogen set free, and the 
higher the pressure. 

If a short circuit exists for any length of time, the pressure 
of the excess hydrogen will speedily ruin it, as the cell will 



GAS, OIL AND STEAM ENGINES 209 

puff up, or even burst under the pressure. If the rate of dis- 
charge be kept so low that all of the gas will be absorbed by 
the manganese, as soon as generated, the cell will furnish a 
steady current until the elements of the cell or the electrolyte 
are exhausted. 

The steady current limit, or non-polarizing limit is about 
one-half ampere and if long life of the cell is expected, the cur 
rent drain should be less than this amount. A good spark 
coil will develop a satisfactory spark on a quarter to one-half 
ampere, so that the demand of a good coil is well within the 
safe limits of battery capacity. The voltage of the average dry 
cell when in good condition is 1.5 volts on open circuit. When 
the cell is old or exhausted, the voltage falls rapidly when any 
demand for current is made on the cell, and the voltage also 
varies with the rate of current flow, the voltage decreasing 
with an increase of current. 

As there is not much difference in voltage between a new 
and old cell when on open circuit, it will be seen that the am- 
meter giving the current output will give a more accurate de-- 
termination of the condition of the battery. The voltage is in- 
dependent of the size of cell. 

The battery showing the greatest amperage is not neces- 
sarily the best for general use, as cells having an unusually high 
current capacity are generally short lived. The strong electro- 
lyte used in high ampere batteries causes them to burn out or 
deteriorate rapidly when not in use. 

Under ordinary conditions, a correctly proportioned No. 6 
ignition cell should show a current of from fifteen to twenty 
amperes on short circuit when the cell is new, although higher 
results may be obtained safely with some makes of cells. 

While the voltage is the same for all sizes of batteries, and 
depends on the material used in the construction, the amperes 
increase with the size of the cell, and the area of the electrodes. 

If a cell does not show more than ten amperes on short circuit, 
it should be thrown out and another substituted for it, as the cell 
is liable to go out of commission at any minute when reaching 
this point of exhaustion. 

A small battery testing voltmeter or ammeter should be in 
the kit of every gas engine operator using a battery for igni- 
tion, as the exact condition of a vital part of the power plant 
can be determined quickly and with accuracy. For dry bat- 
teries an ammeter is preferable; for storage batteries a volt- 
meter must be used. 



210 GAS, OIL AND STEAM ENGINES 

When buying dry batteries insist on having new, fresh cells, 
as any battery depreciates in value with age. Never take a cell 
without testing it, as it is the practice of dealers to work off 
their old stock on unsuspecting customers. Examine the bat- 
tery closely for the makers' dates, and if the battery is several 
months old, it is probable that the electrolyte is dried up or 
that the electrodes are wasted through long continued local 
action. As heat stimulates chemical action in the cell, they 
should be stored in a cool place to retard the wasting action 
as much as possible. Under all conditions, the cell should be 
kept dry, since the moisture that is deposited on the cell forms 
a closed circuit for the current which soon exhausts the battery. 
Cold retards chemical action in the cell and consequently re- 
duces the output in zero weather to such an extent that start- 
ing is frequently impossible. 

Multiple cylinder engines exhaust a battery quicker than 
those with a single cylinder, as there are more current impulses 
in a given time and consequently more current is used. A bat- 
tery may be compared with a bottle that holds a certain quantity 
of fluid. If the water is allowed to drip out slowly it will last 
for a long time, but if allowed to flow in a continuous stream 
will soon be exhausted. 

With badly designed or poorly adjusted spark coil, the de- 
mand on the batteries is greater than with one that is in proper 
condition. An engine that runs continuously exhausts a battery 
faster than one that is run at long intervals. Always open the 
battery switch when the engine is to be idle for any length of 
time, as the engine may have stopped with the igniter in con- 
tact, allowing the battery to expend its energy uselessly. 

Test batteries immediately after a run, as the batteries will 
recover after standing a while, and will show a fictitious value. 

A weak, partially exhausted battery will cause a poor spark 
that will result in misfiring or a loss of power. It is poor 
economy to attempt running an engine on a weak battery. An 
engine may run on a weak battery for a short time, and then 
gradually decrease in speed until it comes to a full stop. Mis- 
firing is generally in evidence as the engine dies down. In 
case of an emergency, weak batteries may be made to run an» 
engine of an automobile or boat to its destination, by stopping 
the engine frequently and allowing the batteries to recuperate 
during the idle periods. A battery that is temporarily weak- 
ened by hard service or by a temporary short circuit will usually 
revive or partially recover its strength if allowed to "rest" for 



GAS, OIL AND STEAM ENGINES 211 

a short time until the hydrogen is absorbed by the depolarizing 
material. The life of a dry cell can be extended for a few 
hours by punching a hole in the sealing wax on the top of the 
battery, and pouring water, or a solution of water and sal- 
ammoniac into the cell. This will reduce the internal resistance 
and increase the current. The batteries will run under these 
conditions for a short time only, and new cells should be pro- 
cured at the earliest possible moment. No old cell can be made 
as good as new by any method. Never drop the cells on the 
floor nor subject them to hard usage mechanically, for if the 
active material is loosened, the current output will be reduced. 
A short circuit through a closed switch with the engine stopped 
or a loose dangling wire will put the cells beyond repair. 

If the binding screw on the carbon electrode does not make 
good contact with the carbon, tighten it to decrease the re- 
sistance. Fasten the connecting wires firmly under the bind- 
ing screws and keep the connections clean. 

In the absence of an ammeter, a rough estimate of the con- 
dition of the cell may be made by fastening a short wire tightly 
in the zinc binding post, and touching the carbon surface 
lightly and intermittently with the free end of the wire. When 
contact is made with the free end of the wire, a small puff of 
smoke will arise and a red spark will be seen if the cell is in 
good condition. 

Sometimes the contact made on the carbon will produce only 
a small black ring on the surface of the electrode. This indi- 
cates a battery that is nearly exhausted, and one which is good 
for only a few more hours of service. 

When a number of cells are connected together in such a 
way that they collectively form a single source of current, the 
group is called a battery, and the resulting voltage and am- 
peres of the group depends on the way in which the cells are 
interconnected. 

It is possible to connect the cells of a battery in such a way 
that total voltage of the group or battery is equal to the sum of 
the voltages of the individual cells. A battery connected in 
this manner is said to be connected in series. While the volt- 
age of a battery is increased, by series connection, the number 
of amperes is the same as that given by a single cell, the same 
current flowing through the set. 

(82) Series and Multiple Connections. 

Fig. 86 shows the cells connected in series, the carbon ter- 
minal of one cell being connected to the zinc terminal of the 



212 GAS, OIL AND STEAM ENGINES 

second. The carbon of the second cell is connected to the 
zinc of the third, and so on throughout the series, the two 
remaining terminals of the battery being connected with the 
ignition circuit. The number of watts or power developed by 
the group is equal to the sum of the outputs of the separate 
cells. If the voltage of each cell shown in diagram is 1.5 
volts, the total voltage of the group of five cells will be 
1.5x5 = 7.5 volts, and if the current of a single cell is 15 
amperes, the current output of the group will be 15 amperes, 
or the same as that of a single cell. Almost all ignition appa- 
ratus now on the market requires six volts for its operation, 
so with cells having a voltage of 1.5 volts such apparatus would 
call for four cells in series, as 6 -f- 1.5 = 4. 

Owing to the increase of internal resistance caused by series 
connections it is usual to add one more cell than is theoretically 
required, making a group of five cells to supply the six volts 




required. A large number of cells will give a hotter spark than 
a smaller, but the excessive current causes the contact points 
of the igniter or vibrator to burn off rapidly and also hastens 
the destruction of the cells themselves. 

Batteries connected in such a way that the total amperes 
of the group is increased without increased voltage are said 
to be connected in multiple or parallel. When batteries are 
connected in multiple, the total current in amperes is equal 
to the sum of the amperes delivered by the separate cells; 
and, while the current in amperes is increased by multiple 
connection, the voltage of the group remains equal to that 
of a single cell. 

If each cell connected in multiple has an electromotive force 
of 1.5 volts, and can deliver 15 amperes, the total current de- 
livered by this system of connection will be 15 X 5 = 75 amperes 
with five cells, and the electromotive force will be 1.5 volts as 
in the case of the single cell. By connecting batteries in multiple, 
the resistance is reduced, allowing a maximum flow of current. 
The demand on the individual cells is reduced by multiple 



GAS, OIL AND STEAM ENGINES 213 

connection, as each cell only furnishes a small part of the 
total current. The greater the number of cells, the less will 
be the current required per cell, with a given total current. 
As the life of a battery depends entirely upon the rate at which 
it is discharged, it is necessary, for economical reasons, to keep 
the current per cell as small as possible, therefore the multiple 
system would prove of value as it reduces the load to the small- 
est possible limit. Enough cells should be placed in multiple 
to reduce the current to less than a quarter of an ampere per 
cell. The cells shown will not have sufficient voltage to oper- 
ate ordinary ignition apparatus requiring a potential of six 
volts, hence the multiple system must be modified in order to 
have an increased voltage, and at the same time secure the 
advantages of multiple connections. 

(83) Multiple-Series Connections. 

A compromise is affected by the multiple series system of con- 
nections in which are combined the advantages of both the 
series and multiple systems of connection. 

This arrangement allows sufficient voltage to operate 6 volt 
apparatus and at the same time reduces the rate of discharge 
on the individual cells. The series-multiple battery shown in 
the diagram 88 consists of four groups of batteries connected in 
multiple, each group of which consists of five cells that are 
connected in series. The current and voltage in the various 
branches is shown in the diagram. The series-multiple system 
is adapted for use with multiple cylinder engines, as engines 
with more than one cylinder cause a severe drain on the igni- 
tion system. Arranging the series groups in parrallel increases 
the life and efficiency of the cells. If an efficient coil is used, 
the drain of a single cylinder is not too great to be met with 
a single set of series cells. If possible the set should be pro- 
vided with a duplicate, so that the load could be transferred 
from one set to the other at proper intervals by means of a 
double throw switch. 

With a single set of batteries in series the working life of 
the cells will be approximately twenty hours under ordinary 
conditions. With four groups of four cells in series, the life 
of the cell will be approximately 160 hours, or eight times the 
life of the single set under similar conditions. 

While the cost of the cells will be only four times that of 
the single set, it will be seen that the cost of battery upkeep 
is halved by reducing the demand on the cells. 



214 



GAS, OIL AND STEAM ENGINES 



Sometimes duplicate sets of series multiple connected bat- 
teries are used for heavy duty engines, the engine running on 
one set for a .while and then on the other, allowing the first set 
to thoroughly recuperate before it is again thrown in service, 
by means of the double throw switch. 

When batteries are multiple or series-multiple connected they 
should be of the same size and make and of the same voltage. 
If the cells are of different voltages useless local currents will 
circulate among the cross-connections, shortening the life of 
the battery and reducing the output. 




Fig. 88. Cells in Multiple Series. 



In connecting a dry cell use a good grade of rubber insulated 
wire, preferably wire with a stranded conductor, as it is less 
liable to break or loosen at the binding screw of the battery. 
Carefully remove the insulation from the end of the wire that 
is to be fastened under the binding screw of the battery. 
Scrape it until it is bright and perfectly free from dirt before 
fastening it in the battery terminal. Never allow a dirty or 
corroded connection or a loose wire to exist. An open battery 
circuit or loose connection will stop engine suddenly, or will 
prevent starting. 

The battery connections should be screwed down tight with 
the pliers, care being taken that the screws are not broken by 



GAS, OIL AND STEAM ENGINES 215 

the tightening process. See that frayed ends of the wire do 
not project beyond the binding screw to which they are con- 
nected and make contact with other cells or metal objects. Be 
sure that no insulation gets between the contact braces of the 
binding screw. 

(84) Operation of Dry Cells. 

The following hints should be observed to obtain the best 
results with dry cells. 

(1) Never remove the paper jackets from the cells. 

(2) Never lay tools or other metallic objects on top of the 
cells for this will cause a "short" that will quickly exhaust them. 

(3) Do not connect old and new cells together, especially 
with the multiple-series system of connections, for the old cells 
will limit the output of the new, or else will cause cross-cur- 
rents that will exhaust all of them. 

(4) When trouble developes in the battery, test each cell 
separately and remove the faulty cells. Do not reject all of 
the battery because of one or two dead cells. 

(5) Place the cells in a wooden box that will protect them 
from dirt or moisture, and if possible divide the box off into 
pigeon holes with a cell in each hole. For the best protection 
against moisture, the. box should be boiled in paraffine. 

(6) Provide a battery switch on the box that will cut both 
leads from the cells completely out of circuit when the en- 
gine is stopped. 

(7) Never place a dry cell in a box that has contained stor- 
age cells unless the box has been thoroughly washed out, for 
the residual acid of the battery will destroy the zinc elements. 

(8) Make all connections firmly with well insulated wire and 
take care that the wire does not make contact with any part 
of the battery except that to which it is connected. 

(9) Keep the battery dry. 

(85) Storage Batteries. 

The purpose of the storage battery is to store or accumulate 
the current generated by a dynamo until so that the current 
will be available when the dynamo is not running. A storage 
cell does not "store" current in the same way that water is held 
in a tank, but returns the energy expended on it through the 
chemical changes caused in the cell by the current. 

When the charging current passes through the storage bat- 
tery chemical changes are produced in the electrodes and 



216 GAS, OIL AND STEAM ENGINES 

electrolyte, and the energy expended on the cell is in the form 
of latent chemical energy, in which state it remains until the 
electrodes are connected with one another by a wire or some 
other conducting medium. When the electrodes are connected 
through an external circuit, the electrolyte acts on the elec- 
trodes causing them to assume their original composition. As 
they pass into their previous chemical condition the latent chem- 
ical energy is converted into electrical energy. The current 
thus produced may be used in the same way as in a primary 
cell. 

When discharging, the action of a storage battery is similar 
to that of a primary battery, the current being produced by the 
action of a fluid on two dissimilar electrodes. Instead of sup- 
plying new elements when the battery is discharged, as in the 
case of the primary cell, the elements are brought back to their 
original state by passing a current through the cell in the oppo- 
site direction to that of the discharge. 

There are several combinations of materials which may be 
used in the making of storage battery electrodes and electro- 
lytes, but with the exception of the lead sulphuric battery and 
the new Edison battery none have proven a commercial suc- 
cess. 

The most common type of storage or secondary cell is the 
lead-sulphuric type in which the electrolyte is dilute sulphuric 
acid and the electrodes are lead plates, covered with a chem- 
ical composition known as the active material. These plates 
usually consist of a lead grid, or lattice frame in the pockets 
of which is pasted the active material. The pockets or lattice 
bars of the plates are for the purpose of supporting the active 
material which is of a weak and spongy nature. The active 
material on the positive plate is usually litharge, while that 
on the negative plate is red lead. 

After charging, the active material on the positive plate is 
.changed to lead peroxide by the action of the current, and the 
active material on the negative plate is changed into spongy 
metallic peroxide. The composition of the active material on 
the plates determines the direction of flow of the discharge, or 
secondary current. The current flows from the positive plate 
to the negative through the external circuit. 

When fully charged, .and in good condition, the positive and 
negative plates may be readily distinguished by their colors, 
the positive plate being a dark brown or chocolate color, and 
the negative a slate or grey color. 



GAS, OIL AND STEAM ENGINES 217 

The positive active material is hard, while the negative may 
be easily cut into by the linger nail. The density of the ma- 
terial changes slightly with the charge, as the material ex- 
pands during the discharge. 

The problem of holding the active material securely to the 
plates during expansion and contraction has been a hard one 
to solve, each manufacturer having some favorite form of grid 
or material plug to which he pins his faith. While great im- 
provements have been made in this direction, it is certain that 
we have not yet reached perfection. Loose active material will 
cause short circuits and will reduce the output of the cell; loose 
active material frequently ruins a cell. 

The current capacity of a storage battery depends on the 
area of the plates or electrodes, and in order to increase the 
capacity of a battery, and consequently the area, it is usual to 
use a number of plates connected in parallel. A number of 
small plates of a given area are to be preferred to two large 
plates of the same area, as the battery will be of a more con- 
venient size. 

Customarily there is one more negative plate than positive, 
so that the extreme end plates in a cell are negative, as the 
positive and negative plates alternate with each other when as- 
sembled. 

An ignition battery usually consists of two negative plates 
and one positive. Cells used for power purposes have as high 
as sixty plates. 

A single cell of storage battery should show about two volts 
when fairly well charged. If more than two volts are desired 
more cells should be connected in series. The total voltage will 
be equal to the number of cells, in series, multiplied by the 
voltage per cell. The voltage per cell should never be allowed 
to drop below 1.7 volts, as the cell is likely to be destroyed 
when operated with a low voltage. Recharge as soon as the 
voltage drops to 1.8 volts. 

The ordinary six volt ignition battery consists of three separ- 
ate cells connected in series, which are encased in one protecting 
box. 

The plates are prevented from touching each other within the 
cell by means of a perforated sheet of hard rubber that is in- 
serted in the space between the plates. The perforations allow 
the liquid to circulate between the plates. 

The storage battery is furnished as standard equipment with 
several well known gas engine builders, and its use is advocated 
by nearly all. When used in connection with a low tension 



218 GAS, OIL AND STEAM ENGINES 

direct current magneto two independent sources of current are 
at hand, either of which will ignite the engine in an emergency. 

With the magneto-storage battery combination, it is possible 
to obtain a few small lights at any time, whether the engine is 
running or not, and the engine is always ready to start on the 
first "over" with the storage battery and a good mixture. 

If a magneto is not used, difficulty is sometimes experienced 
in obtaining a suitable source of charging current, as many 
localities do not possess direct current plants. Batteries may 
be charged from the direct current exciter in an alternating 
current station, or may be charged by an alternating current 
rectifier such as is used by automobile garages. 

The principal objections to the storage cell are: inconvenience 
of charging; sulphating of cell when standing without a charge; 
ease with which the cell is ruined by short circuits; the damage 
caused by the spilling of the electrolyte; and the fact that the 
cell gives no warning of failing or discharged condition. 

Since the composition of the plates depends on the direction 
in which the current flows through the cell, it is obvious, that 
an alternating current which periodically changes its direction 
of flow will first charge the plates and then discharge them al- 
ternately. The result of an attempt at charging with alternating 
current would be that the plates would be in the same or a 
worse condition in a short space of time than they were at the 
beginning. In charging a storage cell care should be taken to 
determine the character of the current, especially when the cell 
is to be charged from a magneto. When under charge, the cell 
is connected to the charging circuit in such a way that the 
current flows backwards through the cell or in a direction 
opposite to that when the cell is discharging. 

(86) Care of the Storage Cell. 

The storage battery should never be left in an uncharged 
condition with the acid electrolyte in the cell, for the solution 
will quickly attack the uncharged plates and combine with them 
to form lead sulphate. As lead sulphate has a high electrical 
resistance and is insoluble in the electrolyte the sulphate coat- 
ing will reduce the output or if present in excess, ruin the cell. 
The sulphate appears as a white coating on the surface of the 
plates. The only remedy for this condition at the hands of the 
average engine operator is a prolonged charge, or over charge, 
at a slow rate. There are several chemical processes but they 
are too complicated for the average man. 



GAS, OIL AND STEAM ENGINES 219 

As sediment collects on the bottom of the battery jars, and 
is liable to cause a short circuit, the plates should be held about 
half an inch from the bottom of the jar. Care should be taken 
that the cells of the stationary type of battery are kept dry and 
clean. Do not allow dirt to drop into the solution as it is 
liable to destroy the cell. 

A volt meter should be used to determine the condition of 
the battery, and should be used frequently. An ammeter should 
never be used on a storage battery, as it is of very low resist- 
ance, and would probably cause a rush of current that would 
destroy both the battery and the instrument. 

Never short circuit a storage battery, even for an instant, as 
excessive current will cause the plates to buckle, or will loosen 
the active material on the plates. 

The plates are immersed in the electrolyte, which should cover 
the entire plate or active surface. If the solution does not 
cover the plate, the capacity of the cell will be reduced. Plates 
that are partially covered with solution deteriorate rapidly from 
"sulphating." This is caused by the air and acid acting on the 
damp inactive portion of the plate. 

Usually the electrolyte consists of a dilute solution of sul- 
phuric acid and water, but in some ignition cells the solution is 
"solidified" by some substance to about the consistency of 
table jelly. The object of this thickened solution is to prevent 
the solution from slopping and leaking when the battery is being 
transported. 

The solution used in a storage battery is exceedingly corrosive 
in its action, and if spilled on metal or wood will destroy it 
immediately. Care should be taken in handling the electrolyte. 

A cell should never be discharged below 1.7 volts for below 
this point, the plates are likely sulphate. When the solution is 
replaced by fresh, or water is added for the purpose of restoring 
the electrolyte to its original level, use only distilled water, free 
from metallic salts and suspended matter. 

Many people "test" their cells by snapping a wire across the 
terminals to "see if there is a good spark." Nothing could be 
more injurious to the battery, and as this test indicates nothing, 
the practice should be discontinued. Make all your tests either 
with a hydrometer or a voltmeter, the latter is preferable in the 
average case. 

The electrolyte is a solution containing approximately 10% 
of chemically pure sulphuric acid and 90% of distilled water. 
The specific gravity of the fluid should be from 1,210 to 1,212 



220 GAS, OIL AND STEAM ENGINES 

in all cases. A standard battery hydrometer should be used by 
all storage battery users to ascertain the exact density of the 
solution as the specific gravity is a direct index to the condition 
of the cell. A gasoline hydrometer is useless for a storage 
battery. 

When mixing the electrolyte it should be placed in a glass 
or porcelain jar, and the process should never be performed in 
the battery -jar in the presence. of the plates. The solution is 
very active chemically and should not be brought into contact 
with metallic or organic substances because of the danger of 
contaminating the fluid. The acid should always be poured into- 
the water in a thin stream while the mixture is being stirred 
with a glass or porcelain rod. Pouring the water into the acid 
is likely to produce an explosion and should therefore be care- 
fully avoided. 

As the acid heats the water during the mixing the hydrometer 
reading should not be taken until the heat caused by the first 
addition of acid has been reduced to that of the room. Taking 
a reading with a hot solution will give inaccurate results, un- 
less, of course, the reading is reduced to normal by the method 
described in a previous chapter. When the reading has been 
taken and found to be correct and the solution has been re- 
duced to the temperature of the room, the electrolyte may be 
poured into the cell through the filler openings in the top of 
the cell. . Pour into each cell sufficient fluid to cover the plates 
but avoid filling the cell to the top, or flooding it. 

At the end of the charging time given by the maker, with- 
draw a sample of the electrolyte by means of a syringe and 
test the specific gravity. This should not be over 1,290 for a 
fully charged cell, and if the solution exceeds this amount, pure 
water should be added until the proper point is reached. Al- 
ways correct the specific gravity in this way every time the 
battery is charged as evaporation and internal chemical changes 
cause the density to change from time to time. The voltage of 
a good storage battery will be about 2.1 volts when fully 
charged. Overcharging is wasteful and finally destroys the 
cell, the effects being similar to those caused by excessive dis- 
charges, that is, buckled plates and loosened active material. 
Overcharging a sulphated battery may cure the trouble, a 
little overcharging at intervals being better than a long con- 
tinued overcharge. 

An increase in the specific gravity of the electrolyte of from 



GAS, OIL AND STEAM ENGINES 221 

30 to 50 degrees, with a corresponding rise of voltage, shows 
that the cell is fully charged. 

After the charging is completed remove all of the solution 
spilled on the battery, preferably by washing, and wipe bone 
dry. If the solution is higher in the air, remove the excess 
with the syringe. 

(87) Make and Break System (Low Tension). 

When a circuit carrying a current is opened or broken at 
any place in its length, an electric spark will occur at the point 
at which the w T ires or contacts are separated. This is due to 
what might be termed the "momentum" of the current which 
causes it to persist in its course even to the extent of jumping 
over a short distance of the highly resistant air in the gap. 
The size and heat of the spark may be increased by placing 
a coil of copper wire in series with the circuit that has an 
iron core in the center of the turns. This coil increases the 
tendency of the current to jump the gap, or in other words in- 
creases the momentum of the circuit. 

Each separation of the terminals of the circuit causes but a 
single spark, so that in order to obtain another the terminals 
must be again brought into contact and the current reestablished 
in the circuit before the circuit is again opened. Thus the func- 
tion of the make and break igniter is to alternately make and 
break the circuit in the presence of the combustible mixture. 
To obtain the greatest spark and most certain ignition, the con- 
tact points should be opened with the greatest possible speed, 
an action that is accomplished in the actual engine by springs 
and triggers. 

A typical cylindrical make and break coil consisting of an 
iron wire core surrounded by a coarse copper wire core is 
shown by Fig. 91. At one end of the coil will be seen the 
two terminal screws by which it is connected with the circuit. 
Another make and break coil is shown by Fig. 92, which has 
the same type of winding, but differs in having the core wire 
coil extended beyond the winding and heads. . By closely exam- 
ining the cut, the iron wires will be seen in the projecting core 
tube at the left end of the coil. A flat base is also provided for 
fastening it to a stationary foundation. 

A typical make and break igniter is shown by Fig. 93, to- 
gether with the usual circuit consisting of a primary coil and 
battery. In this figure, A and C are the two electrodes pro- 
vided with platinum contact points N and O respectively. The 



222 



GAS, OIL AND STEAM ENGINES 



electrode A is stationary and is insulated from the iron casing 
K by the insulating washer H, and the insulating bush- 
ing or tube I. The electrode C is oscillated intermittently by 
the engine through its shaft E, and the trigger G, the springs 
S serving to snap the platinum contact O away from N at 
the proper moment. This electrode (C) is in electrical con- 




Fig. 91. Kingston Cylindrical Make and Break Coil. 



nection with the shell K, and the engine frame at all times, 
and is provided with a brass bushing F for a bearing surface. 
The outer containing casing K is bolted to the combustion 
chamber of the engine by the bolts LL, so that the electrodes 
A and C project into the combustion chamber. 




Fig. 92. Kingston Make and Break Coil. Short Type. 



Current from the battery R passes through the coil winding 
P to the coil terminal U from which it passes from V to the 
igniter binding post J. From J it flows along the rod D to 
the stationary electrode A. Since the rod D is surrounded by 
the insulating washers and tube H, T and I, the current can- 
not escape directly to the casing K. With the two platinum 
points N and O in contact, the current flows through C to the 
shell K from which point it flows back to the battery R through 
the conducting path V, completing the circuit. The greater 



GAS, OIL AND STEAM ENGINES 



223 



portion of the path V consists of the engine frame. When the 
electrode is moved in the direction of arrow B, the current is 
opened and a spark occurs at the point of separation M, in con- 
tact with the gas in the combustion chamber. The electrode 
C being connected with the engine frame is said to be 
"grounded." If the stationary electrode A were not insulated 
from the casting K, the current would pass directly £rom the 
terminal J back to the battery R without passing through the 
contact points at all, and consequently no spark would be pro- 
duced on the separation of the points. 




Fig. 93. Diagram of Igniter and Connections. 



A push rod which is actuated by a cam on the engine, en- 
gages with the trigger G, and causes the spark to occur when 
the piston is on the end of the compression stroke. In nearly 

all engines, the relation between the time of the spark and the 
piston position can be regulated to suit the requirements for 
advance and retard. This adjustment is necessary in i 
that the spark may be varied to meet the difference between 
the starting and running requirements. 

While the ignition should be considerably advanced while 
running, it is necessary to retard it when starting, as the engine 
is liable to "kick back" with an advanced spark. 

This advance and retard device should be accessible while 
the engine is running, and the operator should be able to control 



224 GAS, OIL AND STEAM ENGINES 

the point of ignition at all tifries. Many men have been seriously 
injured by the lack of this device or by neglecting to use it. 

The contact points make contact only for a short time be- 
fore the spark is required in order to reduce the amount of cur- 
rent to the minimum, and therefore increase the life of the 
batteries. 

The duration of the "make" or contact should be as short 
as possible. Prolonged contact weakens the batteries and causes 
them to run down rapidly. For the same reason the electrodes 
should remain separated until the make is actually required. 

A certain period of contact is necessary, however, to allow 
the spark coil to "build up," but with a properly designed coil 
the time required is very short. 

Some engines provide a device that cuts out the ignition 
current altogether during the idle strokes. This adds materially 
to the life of the batteries. 

The igniter should be located near the inlet valve, as the 
cold incoming gases tend to keep it cool and clean, besides 
insuring the presence of combustible gas around the igniter 
electrodes. Improper placing of the igniter will greatly reduce 
the efficiency of the engine. Avoid placing the igniter in a 
pocket, or in the path of the exhaust gases. 

The make and break. ignition system has many good features, 
but cannot successfully be applied to engines running over 500 
revolutions per minute, nor can it be applied to engines of less 
than 3 H. P. as the parts would be too small and delicate to 
be durable. 

The make and break igniter produces the largest and "hottest" 
spark of any type of ignition, and is especially derirable for 
large or slow running engines. Being operated at a low volt- 
age, it is not as easily affected by moisture, poor insulation, or 
dirt as the high tension or jump spark system, nor is it liable 
to give the operator such a violent "shock." 

Engines governing by the "hit and miss" system have a 
device that cuts out the current during the "missed" power 
strokes. This effects a considerable saving in battery current, 
especially on light loads when the engine misses a great num- 
ber of strokes. 

While possessing many points of merit, the make and break 
system is open to several serious objections: 

1. Due to the high combustion temperature there is excessive 
wear of the working parts in the cylinder, this wear causes a 
change in the ignition timing. 



GAS, OIL AND STEAM ENGINES 225 

2. The low voltage used in the make and break system calls 
for perfect contact of the electrodes in the cylinder. This con- 
tact is often interfered with or entirely prevented by the accu- 
mulation of carbonized oil and soot deposited on the surfaces. 

3. The wear of the operating spindle or shaft, which passes 
through the cylinder wall causes leakage, which in turn causes 
a loss of compression in the cylinder. 

4. The wear of the external operating mechanism produces 
a change in the timing. The edge of the fingers, wiper blades, 
etc., tend to cause an advance in the ignition as a general rule, 
with the attendant danger of broken crank shafts. 

5. The system is mechanically complicated, correct operation 
calling for constant care as to adjustment. 

All ignition apparatus wears in the course of time and changes 
the timing of the engine. The electrodes and push-rods wear 
and require readjustment. Generally the tendency of worn 
parts is to advance the ignition. This change in timing occurs 
so gradually that the operator does not notice it until the en- 
gine begins to pound, or until the efficiency has been consider- 
ably reduced. 

When the engine is new it is well to mark the ignition 
mechanism in such a way that the relative positions of the* 
crank and igniter will be shown at the time when the igniter 
trips. It will then be possible for the operator to refer to the 
marks at any time to tell whether his ignition is occurring at 
the proper time. Always mark the half-time gears when tak- 
ing the engine apart for the . difference of one tooth when 
reassembling will be sufficient to throw £he engine out of time. 

The usual method of marking the gears, is to center punch, 
or scratch one tooth on the small gear, and then mark the two 
teeth of the large gear that lie on either side of it. With these 
marks it is possible to replace the gears in their original and 
proper positions. 

The igniter should trip, causing the electrodes to separate 
just before the end of the compression stroke is reached, or 
just before the crank reaches the inner dead center. The dis- 
tance lacking the exact dead center represents the instant of 
time between the time of ignition and the actual pressure es- 
tablished by the combustion. 

As most engines have the ignition considerably retarded when 
starting, the igniter will trip later with the lever in the "start" 
position than when in the "running" position. Never fail to 
retard spark when starting nor forget to advance it when 
engine is up to speed. 



226 GAS, OIL AND STEAM ENGINES 

The actual advance given to an engine depends on the char- 
acter of the fuel and on the speed. 

An engine is said to have an advance of 10°, if the crank 
lacks 10° of having made the inner dead center at the time 
of ignition. 

The most economical point of ignition is easily determined 
when the engine is running on a steady load, by varying the 
point of ignition and noting the position assumed by the gov- 



(88) Operation of the Make and Break Igniter. 

To keep the igniter in order, and to obtain the best results 
with the least trouble, the following hints should be observed: 

(1) Clean the igniter frequently, and remove all deposits of 
oil and carbon. For cleaning, the igniter must be removed 
from the cylinder, care being taken to avoid injury to the pack- 
ing or gasket. Graphite dusted on the gasket will prevent it 
from sticking to either the igniter or cylinder. 

(2) If the contact points are rough, pitted, or covered with 
a carbon deposit, the scale should be removed, and the points 
smoothed down with a fine file, taking care that the two faces 
are filed parallel with one another. 

(3) Insulating washers and tubes should be removed and 
washed in gasoline. The hole through which the igniter rod 
passes should be scraped free from any deposit for much trou- 
ble can be caused by a tight working shaft. 

(4) Examine the hole or bushing through which operating 
spindle passes, for wear. A worn spindle or bushing may cause 
a serious loss of compression; replace worn bushing at once. 

See that the insulation of the stationary electrode is not 
broken. If it is injured in the slightest degree, replace it with 
new. 

(5) Often the sparking points may be cleaned temporarily 
without removing the igniter from the cylinder by pulling upon 
the outside finger or trigger until the points come together, 
and then pushing in towards the cylinder several times on the 
movable electrode, which slides them one on the other, scrap- 
ing off the deposit. This method is only a make shift. 

(6) After removing igniter, replace all wires, screwing them 
firmly into place. The ends of wires and connecting screws 
should be perfectly clean when the conection is made; to insure 
perfect contact, the surfaces should be scraped or sand-papered 
until bright and shining. See that no foreign matter of any 



GAS, OIL AND STEAM ENGINES 227 

kind gets between the wires and the metal of the binding screws. 
Wherever possible connections should be soldered. 

(7) A small coil of the wire should be made at the point of 
connection; i. e., the wire should be a trifle longer than neces- 
sary to reach the binding screw, the excess wire being coiled 
up on a pencil. This coil allows of removing igniter, allows for 
broken wire ends and reduces the tendency to loosen the con- 
nection. 

(8) Ground wires, or wires connected with the frame of the 
engine should receive careful attention. They are generally 
fastened under some screw or bolt on the engine which may 
become loose or fail to make contact, thus opening the entire 
circuit and causing the engine to stop. The ground wires are 
generally connected in inaccessible places, and require all the 
more attention for this reason. 

(9) For the primary of low tension wiring, use only the best 
grade of stranded rubber covered wire. A special wire for igni- 
tion purposes is on the market. It is rather expensive but is 
just the thing for the service. 

Never use cotton covered or waxed wire. This covering af- 
fords absolutely no protection against moisture or abrasion. 

(10) As the voltage of a primary circuit, or circuit for make 
and break is very low, and the current comparatively high, it 
is well to have the copper as large as possible. It should never 
be less than number 14 gauge. Don't use solid wire if you can 
obtain stranded conductor. (Stranded wire is made up of a 
number of fine wires which are twisted into a cable or rope of 
the desired size.) 

(11) Oil destroys rubber insulation and should be kept off the 
wiring. Try to locate the conductors so that they will be out 
of range of oil thrown by the moving parts. 

(89) Jump Spark System (High Tension System). 

Due to its simplicity and the light weight of its moving parts, 
the high tension ignition system is applied to practically all 
small, high speed engines running 500 R.P.M. or over. The 
high tension system is also desirable from the fact that it has 
no moving parts in the cylinder of the engine. 

The principal objection to the high tension system is the 
ease with which the high voltage current leaks or short circuits, 
moisture being fatal to the operation of a jump spark engine. 

Instead of producing the spark by breaking the circuit of a 
low tension current, the spark is produced by increasing the volt- 



228 GAS, OIL AND STEAM ENGINES 

age to such a point that the current will jump directly across 
a fixed gap. To cause the current to jump through the air 
requires an extremely high voltage, and as the battery current 
is very* low it is necessary to introduce a device known as a 
"transformer" to stop the current up to the required tension. 
In addition to the voltage required at atmospheric pressure 
(about 50,000 volt per inch of spark) we must also furnish suffi- 
cient pressure to overcome the increased resistance due to the 
compression in the cylinder. 

Unlike the spark coil used on the low tension make and 
break system, the induction coil or transformer coil has two 
separate and distinct coils, that are thoroughly insulated from 
each other. One coil has a few turns of heavy copper wire 
which is called the primary. The other consists of many thou- 
sands of turns of very fine copper wire, and is called the sec- 
ondary. Both coils are wound around a bundle of soft iron 
wire called the core, from which they are carefully insulated. 
When a battery or magneto current flows through the primary 
coil, the core is magnetized, and throws its magnetic influence 
through the turns of the secondary coil. 

In Fig. 94 the primary coil and the low tension battery and 
magneto circuit are represented by heavy lines. The second- 
ary coil, and high tension circuit are represented by light lines. 

In order to obtain a continuous discharge of sparks it is 
necessary to make and break the current in the primary coil 
very rapidly. This is done by means of the interrupter or 
vibrator, which is indicated in the diagrarh by V. The inter- 
rupter consists ordinarily of a spring A on which is fastened a 
soft iron disc D and a platinum contact point B. When the 
core is magnetized it attracts the iron disc D which is pulled 
toward the core, bending the spring A and breaking the con- 
tact between the platinum point B and C. When the contact 
points are separated, and the current broken, the core loses its 
magnetism, and the spring assumes its normal position, which 
brings the platinum points B and C into contact once more, and 
reestablishes the current through the primary. The core is 
again magnetized and the primary current is again broken, and 
so on. This make and break of the current is thus accom- 
plished automatically, the current being broken many thousands 
of times per minute, the vibrator moving so fast as to cause 
a continuous hum. 

As soon as the current starts flowing, the magnetic force 
spreads out through the secondary coil and threads through the 



GAS, OIL AND STEAM ENGINES 



229 



turns of which it is composed. The instant that the current 
ceases, the magnetic force decreases and the turns are again 
threaded by the magnetic field on its return to the core. 

Thus two magnetic waves are sent through the secondary 




o 

.0 



bfl 



coil, one when the circuit is "made," and one when the circu 
is "broken." 

When a magnetic wave threads or spreads through the tun 
of a coil of wire, a current of electricity is generated in the co 
the quantity and pressure or voltage of which is proportion 



230 GAS, OIL ANl3 STEAM ENGINES 

to the intensity of the magnetism, and to the number of turns 
of wire in the secondary coil. 

Thus it will be seen that at every make and break of the low 
tension current in the primary coil, a current is generated in 
the secondary. As the voltage generated in the secondary is 
roughly proportional to the number of turns in the secondary, 
and as there are many thousands of turns, it is evident that 
the voltage in the secondary will be very high. Thus by the 
use of the induction coil, the low tension battery current is 
transformed into a high tension current of sufficient voltage to 
break down the high resistance of the spark gap. 

The condenser is shown at L which has one wire leading to 
the vibrator spring A, and one wire to the contact screw M. 
The function of the condenser is to absorb the spark produced 
at the vibrator points so that the break is made quickly, produc- 
ing a maximum spark. The intensity of the spark depends upon 
the quickness with which the primary current is broken, and 
if it were not for the condenser the length and intensity of the 
spark would be greatly reduced. This device consists of alter- 
nate layers of paper and tin foil, every other leaf of foil being 
alternately connected to the vibrator spring and to* the con- 
tact screw. 

A method of using two independent sets of battery is shown 
in the diagram, so that either set may be thrown into circuit 
by means of the double throw switch O. When handle J is 
in contact with E, the current of battery set H flows through 
the coil as shown by the arrows. When J is in contact with F, 
the battery C is thrown into circuit. The spark gap is shown 
by X, which represents the spark plug in the cylinder. 

In practice, the portion of the circuit shown by I-U is gen- 
erally formed by the frame of the engine, or is grounded. The 
terminal P of the high tension circuit is always grounded 
through the threaded shell of the spark plug, the grounded 
circuit being shown by the dotted lines. Grounding saves wire 
and many connections, for with P and U connected to ground 
it follows that one binding post will serve the place of one high 
tension and one primary post, making three coil connections 
instead of four. 

In order that the spark will occur in the cylinder of the 
engine at the proper time, a switch must be placed in the pri- 
mary circuit of the soil, that will open and close the circuit 
at proper intervals. Such a switch is called a timer, and is 
always driven by the engine. The timer is connected to the 



GAS, OIL AND STEAM ENGINES 231 

engine shaft in such a way that contact is made at, or slightly 
before, the time at which the explosion is required, and as 
soon as possible after spark occurs the current is cut off. 

For multiple cylinder engines it is usual to provide one coil 
for each cylinder, the primaries of which are controlled by a 
single timer and battery. A high tension wire from each coil 
runs to the corresponding cylinder. Instead of having a num- 
ber of coils with a battery system, there are two or three makes 
that operate with one coil in combination with a special de- 
vice known as a distributor which controls the high tension 
current. The high tension distributor directs the current to the 
proper cylinder that is in the order of firing, the timing being 
performed by a timer similar to that used with multiple coils 
except that a single contact sequent is supplied. 

(90) Vibrator Construction. 

Since the efficiency of the high tension coil depends largely 
on the construction and efficiency of the vibrator, the different 
coil makers have developed various types of vibrators that differ 




Fig. 95. Kingston Vibrator. 

greatly from the simple device shown in the coil diagram in 
details. 

The main objects in view in the construction of a successful 
vibrator are: 

1. To reduce the weight of the moving part as much as pos- 
sible in order to increase the speed of vibration, and to make 
the trembler instantly responsive to the timer. 



232 GAS, OIL AND STEAM ENGINES 

2. To cause the contact points to separate as rapidly as pos- 
sible in order to cause the maximum spark. 

3. To have the contacts as hard and infusible as possible 
to resist wear and the action of the spark between the contacts. 

4. To make any adjustments that may be required, due to 
wear, as simple and accessible as possible. 

The types of vibrators are legion, and we have not the space 
to go into the details of all the prominent makes, but will illus- 
trate and describe two well known types. 

The Kingston vibrator made by the Kokomo Electric Com- 
pany, is a good example of a modern vibrator and is shown in 
detail by Fig. 95. All adjustments between the contact points 
are made by means of the contact screw A which carries a 
platinum point at its inner end. The retaining spring D keeps 
the contact screw from being jarred out of place by the engine 
vibration, without the use of lock nuts. Turning A against the 
vibrator, the tension of the spring B is increased, raising the 
creases the length and heat of the spark, and also increases 
screw decreases the tension. Increasing the tension screw in- 
the current consumption. At N is a separate thin iron plate 
which is acted on by the magnetized core, a rivet fastening the 
plate to the main vibrator spring is shown at the end of the 
spring. The current enters through the lug C, and from this 
point the circuit is the same as shown in the coil diagram. 

(91) Operation of the Jump Spark Coil. 

The spark produced by a coil in good condition should be 
blue-white with a small pinkish flame surrounding it, when the 
gap is % of an inch or less. The sparks should pass in a con- 
tinuous stream with this length of gap without irregular stop- 
ping and starting of the vibrator. Coils giving a sputtering, 
weak discharge that causes sparks to fly in all directions are 
broken down and should be remedied. 

The secondary windings, of coils are often punctured or 
broken down by operating the coil with the high tension circuit 
open, or by trying to cause long sparks by increasing the spark 
gap over Y% of an inch in the open aift Coils are also broken 
down by allowing excessive currents to flow in the primary coil. 
Never cause a spark to jump over y% of an inch. 

High compression in the cylinder shortens the jumping dis- 
tance of a high tension spark. Coils that will cause a stream 
of sparks to flow across a gap of y 2 an inch in the open air 
are often unable to cause a single spark to jump a gap of 3*2 



GAS, OIL AND STEAM ENGINES 233 

of an inch under a compression of 80 pounds per square inch in 
the cylinder. 

Remember that a hot spark causes rapid combustion, and 
will lire a greater range of mixtures and "leaner" charges, than 
a straggling, thin, weak spark. Spark coils that give poor 
results with a long spark gap under high compression are often 
benefited by the shortening of the spark gap. Shortening the 
gap will increase the heat of the spark, and will insure the 
passing of a spark each time that the timer makes contact. A 
good coil should have no difficulty in igniting a piece of paper 
inserted between the wires forming the spark gap in the open 
air. 




Fig. 96. Kingston Dash Coil. 

The adjusting screw affords a means of increasing or de- 
creasing the tension of the vibrator spring, and the amount of 
battery or magneto current flowing through the primary coil. 
Increasing the tension of the spring requires stronger magnetiza- 
tion of the core to break the circuit of the contact points. This 
in turn calls for more current from the battery; hence in order 
to lessen the demand for current on the battery, the tension 
should be as little as possible to obtain the necessary spark. 
An increased tension produces more spark as the magnetization 
of the core is increased, but for the sake of your batteries de- 
crease the tension as much as possible with a satisfactory spark. 

Almost all operators have a tendency to run with too stiff 
a vibrator, and hence use too much current. An efficient coil 
should develop a satisfactory spark with ^4 to 5^ of an ampere 
of current in the primary coil. I have often found coils that 
would work well with y 2 ampere, that were screwed up so tight 
that the coils were consuming 4 to 5 amperes or 8 to 10 times 
as much as they should. 



234 GAS, OIL AND STEAM ENGINES 

A battery ammeter used for testing the current consumed by 
coil will save its cost many times over in batteries and burnt 
points if used at frequent intervals in the primary circuit. 

An automobile or marine engine should be tested for vibrator 
adjustment in the following way: 

Adjust vibrator so that spring is rather stiff. Start engine 
and get it thoroughly warmed up and running at full speed, then 
slowly and gradually decrease the tension of the spring until 
misfiring starts in; then slowly increase tension until misfiring 
stops. Increase the tension no farther; this is the correct ad- 
justment. 

Poor vibrator adjustment is the cause of much trouble and 
expense as it uses up the batteries and wastes fuel. The prin- 
ciples of correct adjustment are simple, the adjustment easily 
made, and there is no possible excuse for the high current con- 
sumption and rapid battery deterioration met in every day 
practice. The usual practice of the average operator is to 
tighten the vibrator until the spark (observed in the open air) 
is at its maximum. This is commonly known as "adjusting the 
coil;" shortly after you hear of him thi owing out his batteries as 
no good. After once getting the vibrator in proper trim the 
ear will give much information as to the adjustment. 

A vibrator adjusted too lightly will cause "skipping" or mis- 
firing with the consequent loss of power. 

Never attempt to operate a coil that is damp; the coil will be 
ruined beyond repair. Above all, do not place the coil in a 
hot oven to dry, as the box is filled with wax, and if this is 
melted it will run out and reduce the insulation of the coil. Dry 
coil gradually. 

If the batteries are new or too strong the vibrator may be 
held against the core of the coil so that the vibrator will not 
buzz. If this is the case loosen the screw until it works at the 
proper speed. If the batteries are weak, the coil may not be 
magnetized sufficiently to draw the vib'rator and break the cir- 
cuit. If this is the case tighten the screw. If the vibrator 
refuses to work with the battery and wiring in good condition, 
and if you are sure that the current reaches the coil, look for 
dirty or pitted contacts on the vibrator. 

Should the contact points be dirty, clean them thoroughly 
by scraping with a knife or sandpaper. Water on the points 
will stop the vibrator, as will oil or grease. 

If contact points are of a uniform gray color on their con- 
tact surfaces, and are smooth and flat without holes, pits or 



GAS, OIL AND STEAM ENGINES 235 

raised points, they are in good condition. If pits, discolorations 
or projections are noted, the contact surfaces should be brought 
to a square, even bearing by means of a small, fine file. The 
point should not come into contact on an edge, but should 
bear on each other over their entire surface. Do not use sand 
paper to remove pitting, as it is almost impossible to secure an 
even, flat surface by this means. 

It is best to remove the contact screw and vibrator blade for 
examination and cleaning, as it is much easier to file the points 
square and straight when removed from the coil. 

Be careful not to bend the vibrator spring when cleaning, as 
the adjustment will be impaired. When replacing contact screw 
and vibrator blade in coil, be careful that they are in exactly 
the same relative position as they were before removing. Also 
be sure that the contacts meet and bear uniformly on their 
surfaces. 

(92) Primary Timer. 

The duty of the primary timer is to close the primary circuit 
of the spark coil at, or a little before the time at which the 
explosive of the charge is required. The exact time at which 
the timer closes the circuit depends on the load, the speed, and 
the nature of the fuel. The lapse of time between the instant 
that the timer closes the circuit and the instant at which the 
piston reaches the end of the compression stroke is called the 
"advance" of the timer. When the timer closes the circuit after 
the piston reaches the end of the stroke, the timer is said to be 
"retarded." The timer is constructed so that the time of igni- 
tion or the advance and retard can be varied between wide 
limits. Advancing the spark too far will cause hammering and 
power loss as the piston will work against the pressure of the 
explosion. 

Retarding the spark will cause a loss of power, as the com- 
pression will be less when the piston starts on the outward 
stroke; and also for the reason that more of the heat will be 
given up to the cylinder walls as the combustion will be slower. 
The pressure in the cylinder is less with retarded ignition. 
Greatly retarded ignition often causes overheating of the cyl- 
inder walls, especially with air cooled engines, and also over- 
heats and destroys the seat and valve stem of the exhaust valve. 
Do not expect the engine to develop its rated horse-power or 
run efficiently with a late, or retarded spark. 

When the engine is installed, and before the timer wears or 



236 GAS, OIL AND STEAM ENGINES 

has a chance to get out of adjustment, look it over carefully 
and see whether the maker has left any marks relating to the 
timing of the spark. If there are no marks, it is well to deter- 
mine the relation between the position of the piston and the 
timer, as the efficiency of the engine depends to a great degree 
upon the firing point. 

Timers are advanced and retarded by partially rotating the 
housing either in one direction or the other. When the timer 
is mounted directly on the cam shaft with the cam shaft travel- 
in a direction opposite to that of the crank shaft, the timer will 
be retarded by moving it in the same direction as the cam 
shaft travels, moving it against cam shaft rotation advances 
the spark. 

Timers for two stroke cycle engines rotate at crank shaft 
speed, and the direction of advance and retard varies with the 
methods adopted for driving the timer. 

(93) Timer Construction. 

Fig. 97 shows a typical timer and circuit arranged for a four 
cylinder engine. The device can be arranged for any number 
of cylinders, however, by changing the number of sectors, the 
sectors being equal to the number of cylinders. There are 
timers on the market that differ from the one shown, in the 
diagram but the principle of operation is the same with all. The 
shaft E is usually connected to the cam shaft and is electrically 
grounded to the engine frame at L by means of the bearing in 
which the shaft rotates. 

The lever F mounted on the shaft E carries the pivoted arm 
H which is free to move on the pivot to a limited extent to 
allow for wear on the walls W-W-W-W. At one extremity of 
H is the roller I which rotates on the pin J, as the roller runs 
around W-W-W-W. At the other extremity of H is fastened 
the spring S, which forces I into contact with the walls. 
A-B-C-D are metallic contact sectors whose connections lead 
to the four spark coils. 

When the metal roller I comes into contact with one of the 
sectors as at B, the sector is grounded to the engine frame by 
the roller, the current traveling through the roller and its pin, 
through lever H and its pin, through the lever F and shaft E to 
ground at L, the course of the current being indicated by the 
arrows. 

As the shaft E rotates and carries with it roller I, the roller 
makes contact with the sectors in order B-C-D-A, if rotated in 



GAS, OIL AND STEAM ENGINES 237 

the direction shown by arrow, which rotation grounds the pri- 
mary coils of the spark coils R^-R^-Ri-R 2 in succession; the 
connection from the timer to the primary being to the primary 




R' 



P' T 



TC 



R 2 



P z T* 




R- 



p 3 T 3 



Ssf 



R* 



P» T* 



P-JI* 



K &}£ 





Fig. 97. Timer Diagram. 

binding posts V^-V^-Y 1 -^ 2 . A high tension spark occurs at each 
contact of the roller with the sectors, as the contact allows cur- 
rent to flow through the primary of the coils. The high tension 



238 GAS, OIL AND STEAM ENGINES 

binding posts S 1 -S 2 -S 3 -S 4 are connected with the spark plugs 
or spark gaps \] 1 -U^-U z -\] i by means of high tension cables. 
As soon as the timer grounds a coil, the coil produces a high 
tension spark in its corresponding spark plug. 

It is evident from the foregoing that the timer not only deter- 
mines the time at which a spark will take place, but it also 
determines the cylinder in which the spark will be produced, 
providing of course that a spark coil is provided for each 
cylinder. 

The contact sectors A-B-C-D are insulated from each other 
by the insulating walls W-W- W-W, the inner surface of which 
provides a path on which the contact roller I revolves. 

The contact sectors and insulating walls are encased by the 
protective housing Z, to which they are rigidly fastened. 

The housing Z can be moved back and forth on the shaft E 
for advance and retard, by means of the lever K. 

The current flows from the battery terminal V (with-the roller 
in the position shown) through the switch M, through coil R 3 , 
post P 3 to sector B, from which it passes through the roller I, 
levers H and F to ground. From the ground on the engine 
frame the current flows back to its source, the battery O, thus 
completing the circuit. When the roller makes contact with 
sector C, the coil R 4 is energized, contact with D energizes R 1 , 
and so on. No two coils can be thrown on simultaneously as 
only one coil is grounded at a time. The high tension current 
flows from each coil to its plug as soon as the current passes 
through the primary of that coil. 

In some timers, the current is taken from the revolving arm 
through a separate connection to ground instead of grounding 
the shaft through the bearings. With these timers, the connec- 
tion is not affected by worn bearings or an oil film that tends 
to insulate the shaft from the bearings. 

(94) Operation of Timers. 

Timers frequently cause misfiring which is generally due to 
dirt or oil getting between the contacts, or to the wear of the 
insulating walls W-W-W-W, or to the wear of the moving parts. 

Dirt or gummy oil will prevent the contact coming together 
and completing the circuit, or will clog up the rollers or levers 
so that they cannot perform their functions properly. This 
will of course interfere with production of the spark. 

The contacts and moving parts of the timer should be kept as 
clean as possible, all dirt and heavy oil being removed by means 



GAS, OIL AND STEAM ENGINES 239 

of gasoline at regular periods. Make a practice of cleaning out 
the timer at intervals not greater than one month; oftencr if 
possible. 

Parts subject to wear, such as the roller pin J and the bear- 
ings should be well lubricated, none but the lightest oil being 
employed for this purpose. Heavy grease will gum the con- 
tacts and cause trouble. There should be no rough places or 
shoulders on the contact sectors or on the walls W-W-W-W 
as roughness will cause the roller to jump over the high places 
which in turn result in misfiring. The remedy is to machine 
the surfaces of the sectors and walls by grinding or turning in 
the lathe. Care should be taken in this operation to have the 
interior perfectly smooth and the sectors perfectly flush with 
the walls. Repair black or burnt sectors immediately by grind- 
ing or sand paper. 

Burnt spots or blackened surface on the contact sectors pre- 
vent good contact between roller and sector, sectors should 
show a bright, shining metallic surface. 

Sometimes the insulation warps or swells above the contacts 
so that the roller jumps over the contacts without touching 
them, or if for any reason that contact is made under these 
conditions, it is of a short period and results in a poor spark. 

Timers often make good contact when starting, or at low 
speed, and misfire badly at high speed. This will be caused 
generally by the contact sectors or insulation projecting beyond 
one another, the roller has time to make good contact at low 
speed but jumps over the sector at high. 

The roller I may become rough or develop a flat stop which 
will cause it to jump over the contact occasionally, or it may 
become loose on its bearing pin J, causing intermittent misfiring. 

The wearing or loosening of pins J and X result in poor con- 
tact. Should pin J fall out of the lever H, the roller would drop 
out of the fork and cause serious damage. This has happened 
in two cases to my knowledge. 

Should the spring G weaken or break, contact will be made 
intermittently at high speed, and no contact at low. In this 
case it would probably be impossible to start the engine. In case 
the spring breaks, a rubber band may be used temporarily. 
Wire connections to the timer should be examined frequently 
as the continual back and forth movement tends to twist and 
loosen the wire. Use stranded or flexible wire for these con- 
nections, if possible. 

Before removing the timer mark the hub and the shaft so 



240 GAS, OIL AND STEAM ENGINES 

that the hub can be properly replaced. If this is not done the 
engine will be out of time with the usual results of hammer- 
ing or power loss. 

Should the gears which drive timer shaft be removed, be sure 
and mark the teeth of both gears in such a manner that there 
will be no mistake possible in reassembling them. Mark a to©th 
on the small gear by scratching or with a center punch (the 
tooth selected should be in mesh with the large gear). Then 
mark the two teeth of the large gear that lay on either side of 
the marked tooth of the small gear. Thus it will be easy to 
locate the proper relative position of the two gears at any 
time. 

(95) High Tension Spark Plug. 

The high tension spark plug is a device that introduces the 
spark gap and spark into the combustion chamber, and at the 
same time insulates the current carrying conductor from the 
cylinder walls. Since the voltage of the jump spark current 
is very high it is evident that the insulation of the plugs must 
be of a very high order and that this insulation must be capable 
of withstanding the high temperature of the combustion cham- 
ber. A cross-section of a typical plug is shown by Fig. 98, to- 
gether with its connections and the course of the current, the 
latter being shown by the arrow heads. 

The electrode B through which the current enters the cylinder 
is thoroughly insulated from the walls by the porcelain rod C. 

The porcelain forms a gas tight joint with the threaded 
metal bushing F at the point P, the tension caused by the elec- 
trode B and the nut I holds the porcelain firmly on its seat at P. 

The nut is supported by the porcelain shell H which rests 
in the top of the metal bushing F. A washer L is inserted be- 
tween H and F to insure against the leakage of gas from the 
plug should a leak develop at P. L being a soft washer (usually 
asbestos) allows the porcelains C and H to expand and contract 
without breaking. A packing washer or gasket is also placed 
at the point where the electrode B passes through the porcelain 
H. This is the washer Q, held in position by the nut I. This 
washer is elastic and reduces strain on porcelain caused by the 
expansion. 

The cylinder wall G has a threaded opening R into which 
the plug is screwed, the threads of the opening corresponding 
with the threads on the metal sleeve E. The plug may be 
removed from the cylinder for examination without disturbing 



GAS, OIL AND STEAM ENGINES 



241 



the adjustment of the electrode and porcelains by unscrewing 
it at R. 

Allowing the current to jump from the electrode to the cyl- 
inder wall via the metal sleeve saves one wire and connection, 
the cylinder and the frame of the engine serving as a return 
path for .the current. This simplifies the wiring and minimizes 
the danger of high tension short circuits. 




Fig. 98. Cross-Section of Typical Spark Plug. 



By unscrewing the threaded metal bushing F it is possible 
to examine the condition of the porcelain rod C at the point 
where it is exposed to the heat of the cylinder. This inspection 
can be made without disturbing the packed joints at L or Q. 

In the high tension, or jump spark system, the spark gap 
D-K is of fixed length, hence there are no moving parts or 
contacts within the cylinder to wear, to cause leakage of gas, 
or to cause a change in the timing. This advantage is offset 



242 GAS, OIL AND STEAM ENGINES 

to some degree by the difficulty experienced in maintaining the 
insulation of the high tension current. 

The high tension current leaves the spark coil M at the bind- 
ing screw N, flows along the wire J, and enters the spark plug 
at the binding screw A. From the binding post the current 
follows the central electrode B to its terminal at D. At D a 
break in the circuit occurs which is called the spark gap. It 
is at this point that the spark occurs, the current jumping from 
D to point K through the air. Point K is fastened in the 
threaded metal sleeve E which is in turn screwed into the cyl- 
inder wall G or ground. From the ground the current returns 
to its source through binding post O to the coil. The spark 
therefore occurs inside of the cylinder wall and in contact with 




Fig. 99. Bosch Spark Plugs 

the combustible charge, at the point marked "spark" in the cut. 

If the fuel, lubricating oil, and air are not supplied in proper 
proportions, soot will be deposited on the lower surface of the 
porcelain, and as soot is an excellent conductor of high tension 
current, the current will follow the soot rather than the high 
resistance of the spark gap, a condition that will result in mis- 
firing or a complete stoppage of the motor. Carbonized lubri- 
cating oil or moisture have the same effect. 

Preventing the deposits of soot, moisture and carbonized oil 
is the chief object of plug manufacturers, many of whom have 
brought out designs of merit. In fact the problem of elimina- 
tion of soot is the principal cause of the many types of plugs 
now on the market. 

While many plugs differ in minor refinement of detail from 
the typical plug shown, the connections and general construe- 



GAS, OIL AND STEAM ENGINES 243 

tion are the same in all types, the spark being produced in a 
gap of fixed length which is insulated from the cylinder. 

A well known form of plug, the Bosch, is shown by Fig. 99 
a-b. In this plug a special material known as Steatite is # used 
instead of the usual porcelain. The three external electrodes 
surrounding the center electrode is a particularly efficient ar- 
rangement, especially for magnetos. A peculiar form of pocket 
minimizes the soot problem. 

As porcelain is brittle and is easily broken by the effects of 
heat or blows, mica insulation is often used in place of the 
porcelain. The central core of a mica plug is formed by a 
stack of mica washers, which are held in place by the central 
electrode and the upper lock nuts. 

A poorly constructed mica plug is easily destroyed by a 
weak, stretching, electrode, or by an overheated cylinder. The 
latter causing the washers to shrink and admit oil between the 
layers of mica washers causes a short circuit. As soon as the 
mica washers loosen and separate, they should be forced to- 
gether by means of the mica lock nuts on the top of the plug. 

If by any reason the mica core becomes saturated with oil, 
it is best to obtain a new one, as it is almost impossible to 
remove the oil by simple means open to the average operator. 

The chief value of a mica plug lies in its toughness and me- 
chanical strength, a good mica plug being practically indestruct- 
ible. 

When heated, porcelain does not expand at the same rate as 
the metal sleeves, hence in poorly designed or imperfect plugs, 
heavy strains are thrown on the delicate porcelains which causes 
them to crack. When a crack develops it provides a lodging 
place for soot and carbon which of course causes a short circuit. 
Should a compression leak occur through faulty packing be- 
tween the porcelain and sleeve, it should be immediately tight- 
ened up for eventually it will leak enough to destroy the plug 
or reduce the output of the engine. 

When ordering a plug be sure that you know the size and 
type required by your engine. Some engines require a longer 
plug to reach the combustion chamber than others. Never in- 
stall a shorter plug than that originally furnished with the en- 
gine. Be sure that the plug is not too long as it may interfere 
with the action of the valves or may be damaged by them. 
Plugs are furnished with several threads and taps, i. e. : 

y 2 inch pipe thread (Generally used on stationary engines). 

Metric Thread (Generally used on imported autos). 



244 GAS, OIL AND STEAM ENGINES 

% inch A. L. A. M. Standard (Used on Domestic automobiles). 

Using a plug in a hole tapped with the wrong thread will 
destroy the thread in the cylinder casting and cause compression 
leaks. 

(96) Care of Spark Plug. 

Porcelains are often broken by screwing the plug too tightly 
in a cold cylinder, as the cylinder expands when heated and 
crushes the frail plug. A plug installed in this manner is diffi- 
cult to remove as the expanded walls grip the thread. The 
plug should be screwed in just enough to prevent the leakage 
of gas. A short thin wrench should be used in screwing the 
plug home such as a bicycle wrench. A wrench of this type 
is so short that it will be almost impossible to exert too much 
force, and will be thin enough to avoid any possible injury 
to the packing nut. Bad leaks may be detected by a hissing 
sound that is in step with the speed of the engine, small leaks 
may be detected by pouring a few drops of 'water around the 
joint. If a leak exists bubbles will pass up through the water 
and show its location. 

Plugs are more easily removed from a cold cylinder than a 
hot. If the plug sticks when the engine is cold and is impossi- 
ble to remove with a moderate pressure on the wrench squirt a 
few drops of kerosene around the threads. Never exert any 
force on the porcelain or insulation. The high tension cables 
should be connected to the plugs by means of some type of 
"Snap Terminal," such terminals may be had from automobile 
dealers. 

These terminals make a firm contact with the plug and do 
not jar loose from the plug by the vibration of the engine. They 
are easily disconnected when the inspection of the plug becomes 
necessary, and are generally a most desirable attachment. 

The high tension cable should be firmly connected to the 
plug terminal under all circumstances. A loose connection will 
cause misfiring or will bring the engine to an abrupt halt. If 
snap terminals are not used the plug binding screw should be 
screwed down tightly on the wire. When making connections 
see that the wire is bright and clean, and that frayed ends of 
the wire do not project beyond the plug and make contact with 
other parts of the engine. 

A large percentage of high tension ignition troubles are due 
to short circuits in the spark plug which are generally caused 
by deposits on the surface of the plug insulation. Soot or oil 



GAS, OIL AND STEAM ENGINES 245 

may be removed from the plug by scrubbing the porcelain and 
the interior of the chamber with gasoline applied by a tooth 
brush. Examine the plug for cracks, and if any are found, re- 
place the porcelain or throw the plug away. A cracked por- 
celain is always a cause of trouble. 

To test a plug for short circuits, remove it from the cylinder, 
reconnect the wire, and lay the sleeve of the plug on some 
bright metal part of the engine in such a way that only 
the threaded portion is in contact with the metal of the 
engine. Close the switch and see if sparks pass through 
the gap. If no sparks appear, and if the coil is operating prop- 
erly, clean the plug. As an additional test for the condition of 
the coil, hold the end of the high tension cable about Y^ inch 
from the metal of the engine while the coil is operating. If a 
heavy discharge of sparks takes place between the end of the 
cable and the metal of the engine, the coil is in good condition. 

If a partial short circuit exists, the spark at the gap will be 
weak and without heat; the result wall be intermittent, or mistfir- 
ing with a loss of power. Moisture in the cylinder is a common 
cause of plug short circuits, the moisture coming from leaks 
in the water jacket or from the condensation of gases in a cold 
cylinder. A drop of water may bridge the spark gap, allowing 
the current to flow from one electrode to the other without 
causing a spark. 

If a cloud of bluish wdiite smoke has been issuing from the 
exhaust pipe before the misfiring started, you will probably 
find that the trouble is due to sooted or short circuited plug. 

The remedy is to decrease the amount of lubricating oil fed 
to the cylinder. 

When a magneto is used the intense heat of the spark causes 
minute particles of metal to be torn from the electrodes and 
deposited on the insulation as a fine metallic dust. This will 
of course cause a short circuit and must be removed. Short 
circuits are sometimes caused by the magneto current melting 
the electrodes -and dropping small beads of the metal between 
the conductors. All metallic particles should be removed from 
the plug. 

While a spark plug may show a fair spark in the open air 
test, it will not always produce a satisfactory spark in the cyl- 
inder on account of the increased resistance of the spark gap 
due to compression. 

Compression increases the resistance of the spark gap enor- 
mously and thin, highly resisting carbon films that would cause 



246 GAS, OIL AND STEAM ENGINES 

very little leakage in the open air will entirely short circuit the 
gap under high pressure, the current taking the easiest path 
which in the latter case is the carbon deposit. 

In order to produce conditions in the open air test similar 
to those in the cylinder we must devise some method of in- 
creasing the resistance of the spark gap in the open air above 
any possible resistance that could be offered by the carbon film. 

Placing a sheet of mica or hard rubber between the electrodes, 
or in the spark gap, will increase the resistance to the required 
degree. If the spark plug is in good condition the spark will 
jump from the insulated terminal to the shell when the mica 
is in the spark gap, but if a short circuit exists the current will 
go through it without causing a spark. It is assumed that the 
battery and coil are in good condition when making the above 
test. 

If the electrodes or spark points are dirty they should be 
cleaned with fine sand paper, special attention being paid to 
the surfaces from which the spark issues. When reassembling 
the plug, see that all of the washers and gaskets are replaced 
and that the length of the spark gap is unchanged. A little 
change in the spark gap may make a great change in the spark. 
A good spark is blue white with a faint reddish flame sur- 
rounding it. When the discharge is intermittent or sputters in 
.all directions, either the coil or the plug are partially short cir- 
cuited. Always have a spare plug on hand. 

Ordinarily the length of the gap or the distance between the 
electrodes should be about ft inch for batteries, and a trifle less 
for magnetos. A silver dime is a gpod gauge for the gap. If 
the engine misfires with the coil and batteries in good condi- 
tion, try the effects of shortening the gap a trifle, usually this 
will remedy the difficulty. Exhausted batteries may be made 
operative temporarily by closing up the plug gap to 1/64 inch or 
even less. Shortening the gap increases the heat of the spark 
and nothing is gained by having it over ft inch. 

Almost all high tension magnetos have visible safety spark 
gaps that show instantly the presence of an open circuit in the 
secondary or high tension circuit. If an open circuit exists, 
a stream of sparks will flow across the safety spark gap at low 
speed. 

To determine the cylinder that is misfiring in a four cylinder 
engine proceed as follows: 

Remove cover on spark coil, and hold down one vibrator 
spring firmly against the core while the engine is running. 



GAS, OIL AND STEAM ENGINES 247 

If the engine speed is not decreased by cutting this coil out 
of action, it is probable that this is the coil connected to the 
misfiring cylinder. Now release this vibrator and proceed to 
the next coil, and hold its vibrator down. If this decreases the 
speed of the engine you may be sure that the first coil is in the 
defective circuit. If the vibrator buzzes on the coil under in- 
spection the trouble will be found in the plug. 

Cutting out a coil connected to an active cylinder decreases 
the speed of the engine. Cutting out the coil connected with a 
dead cylinder makes no difference. 

(97) Magnetos. 

A magneto is a device that converts the mechanical energy 
received from the engine into electrical energy, the electricity 
thus produced being used to ignite the charge in the engine. 
This appliance does away with all of the troubles incident to 
a rapidly deteriorating chemical battery and produces a much 
hotter and uniform spark. A magneto is especially desirable 
with multiple cylinder engines where the demand for current 
is almost continuous, as the amount of current delivered by 
the magneto has no effect on its life or upon the quality of the 
spark. 

The principal parts of the generating system of the magneto 
are the magnets, the armature, the armature winding, and the 
current collecting device, of which the armature and its wind- 
ings are the rotating parts. The production of current in the 
magneto is the result of moving or rotating the armature coil 
in the magnetic field of force of the magnets. When any 
conductor is moved in a space that is under the influence of a 
magnet a current is generated in the conductor which flows in a 
direction perpendicular to the direction of motion. The value 
of the current thus generated depends on the strength of the 
magnetic field, the speed with which it is cut, and the number 
of conductors cutting it that are connected in series. Roughly, 
the voltage is doubled, with an increase of twice the former 
speed, and with all other things equal, the voltage is doubled 
by doubling the number of conductors connected in series. 

By employing powerful magnets, and a large number of con- 
ductors (turns of wire) on the armature it is possible to ob- 
tain sufficient voltage for the ignition system at a compara- 
tively low speed. The number of amperes delivered depends 
principally upon the internal resistance of the armature and the 
external circuit, and not on the number of conductors, nor 



248 GAS, OIL AND STEAM ENGINES 

directly upon the strength of the field. For this reason, low 
voltage machines ';hat are intended to deliver a great amperage 
have only a few conductors of large cross section, while high 
tension machines have a great number of conductors of small 
size. In all cases the magneto, or ignition dynamo must be 
considered simply as a generator of current in the same way 
that a battery is a source of current since the current generated 
by them is utilized in precisely the same way. 

The class of ignition system on which the magneto is used 
determines the class of the magneto. The low tension mag- 
neto is used principally for the make and break system, 
although it is sometimes used in connection with a high ten- 
sion spark coil or transformed in the same way that a bat- 
tery is used with a vibrator coil. The high tension magneto is 
used exclusively with the jump spark system and high tension 
spark plug. 

These classes are again subdivided into the direct and alter- 
nating current divisions, depending on the character of the cur- 
rent furnished by the magneto. Briefly a continuous current is 
one that flows continually in one direction while an alternating 
current periodically reverses its direction of flow. As the alter- 
nating current magneto is the most commonly used type, we 
will confine our description to this class of magneto. The 
alternating current magneto is much the simplest form of ma- 
chine as it has no commutator, complicated armature winding, 
nor field magnet coils, and in some types the brushes and 
revolving wire are eliminated. 

As the magnetic flux of an alternating magneto is changed 
in value, that is increased and decreased, twice per revolution, 
it follows that the current changes its direction twice for every 
revolution of the armature. Each change in the direction of 
current flow is called an alternation. 

The voltage developed in each alternation or period of flow 
is not uniform, the voltage being low at the start of the alter- 
nation, rapidly increasing in voltage until it is a maximum at 
the middle, and then rapidly decreasing to zero, from which 
point the current reverses in direction. As we have two such 
alternations, in a shuttle type magneto, per revolution we have 
two points at which the maximum voltage occurs; that is in the 
center of each alternation. These high voltage points are called 
the peak of the wave and consequently the sparking devices 
should operate at the peak of the wave or at the point of high- 
est voltage. The spark therefore should occur when the shuttle 



GAS, OIL AND STEAM ENGINES 249 

or inductors, are at a certain fixed point in the revolution at 
which point the peak of the wave occurs. The peak of the 
wave occurs when the shuttle is being pulled or turned away 
from the magnets. 

In what is known as the "shuttle type" alternating current 
magneto, the generating coil is wound in the opening of an 
"H" type armature. This iron armature core is fastened rigidly 
to the driving shaft and revolves with it. As the armature 
revolves, it is necessary to collect the current that is generated 
by means of a brush that slides on a contact button B, the 
button being connected to one end of the winding. 

(98) Low Tension Magneto. 

The winding of the low tension magneto consists of a few 
turns of very heavy wire or copper strip, one end of which 
is grounded to the armature shaft and the other passing 
through the hollow shaft from which it is insulated. The end 
of the insulated wire is connected to the contact button (B) 
on which the current collecting brush presses. As one end of 
the winding is grounded, one brush, and one connecting wire is 
saved as the current returns to the magneto through the frame 
of the magneto. As the shuttle revolves between the magnet 
poles the magnetism is caused to alternate through the iron of 
the armature, thus causing the current to alternate in direction 
and fluctuate in value. ♦ 

Since there are only two points at which the maximum cur- 
rent can be collected during a revolution with the alternating 
current magneto, it is necessary to drive it positively through 
gears, or a direct connection to the shaft so that this maximum 
point of voltage will always occur at the same point in regard to 
the piston position. If it is driven by belt without regard to the 
position of the piston, it is likely that there will be many times 
that the voltage is zero or too low in value when the spark is 
required in the cylinder. Alternating current magnetos must 
be positively driven, and the armature must be connected to the 
engine so that the peak of the wave occurs at, or a little before 
the end of the compression stroke. 

With this type of magneto the only point that is likely to 
give trouble is the point at which the brush makes contact with 
the contact button. If the brush should stick or not make con- 
tact, or if the button is dirty or rusty, the current will not 
flow; this point should always be given attention. Outside 



250 GAS, OIL AND STEAM ENGINES 

of this the only attention necessary is to keep the bearings oiled. 
Fig. 101 and Fig. 102 show the Sumter low tension magneto as 
arranged for make and break ignition. The armature and its 
connections are of exactly the same type as that shown in the 
previous diagram. The magnets and frame are arranged to 
tilt back and forth so that the peak of the wave will occur at 
the advanced and retarded positions of the igniter. This ar- 




Fig. 101. Sumter Magneto Advanced. Fig. 102. Sumter Magneto Retarded. 



rangement allows the full voltage of the magneto to be obtained 
at any point within the range of the ignitor, an important item 
when starting the engine or running at low speed. When 
mounted on the engine, as shown by Fig. 103, the magnets are 
provided with an operating rod that is marked "start" and 
"run." When the pin on the engine bed is engaged under 
"start," the magneto is retarded, when the pin is under "run" 
it is advanced. A number of intermediate points are provided 
at which the operating arm is held fast by tooth engagements 
as shown in the slotted handle. As shown in the illustration 
the magneto is fully advanced. The gears by which the mag- 



GAS, OIL AND STEAM ENGINES 



251 



neto is driven are clearly shown in the cut, the ratio between 
the gear on the crank shaft and that on the magneto shaft be- 
ing exactly 2 to 1. One lead is carried to the make and break 
igniter in the cylinder head, the current being returned through 
the bed of the engine. The same make of magneto is shown 




w 



bo 



mounted on a vertical engine in Fig. 104. In this case the 
magneto is positively driven from the crank shaft of the engine 
by a chain. The single conductor running from the magneto 
to the cylinder heads is clearly shown. To start the engine, 
the igniter is set in the usual manner and the magneto tilted to 
starting position, as shown in the illustration. The engine is 
then started in the usual manner and, when running, the igniter 
is changed to running position, and the magneto is tilted out- 



252 GAS, OIL AND STEAM ENGINES 

wardly. It is not important which is changed first, the magneto 
or the igniter. It is easy to remember the "starting" and run- 
ning "position" of the magneto, the running position always be- 
ing that in which the magnetos are tilted in the direction 
opposite to that in which the engine runs. 

(99) Care of Low Tension Magnetos. 

(1) Avoid setting a magneto on an iron or steel plate, unless 
stated otherwise in the manufacturer's directions, as in some 
makes the magnetism will be short circuit by iron or steel and 
will reduce the output. 

(2) Do not jar magnets or magneto unnecessarily, for this 
tends to weaken the magnets. 

(3) Never remove the magnets if it can possibly be avoided. 
If this must be done, mark the magnets and gears so that they 
may be replaced in exactly the same position. If your mag- 
neto refuses to generate after reassembling it is probable that 
they are reversed in position or that the magnetism has been 
knocked out of them while off .of the magneto. 

(4) As soon as the magnets are removed, or better before, 
place a plate of iron or steel across both ends of the magnet. 
Don't leave the magnets without this keeper for any length of 
time or they will lose their magnetism. The best plan is to 
leave the magnets alone. 

(5) Remember that the running clearance between the mag- 
nets and armature is very small, only a few thousandths of an 
inch, and that any error in replacing the bearings in their proper 
position will cause the armature to bind in the tunnel. Handle 
armature carefully and do not lay it in a dirty place as a bent 
shaft or grit in the armature tunnel will fix it permanently. 

% (6) Most all magnetos are practically water proof, but don't 
experiment with the hose. 

(7) Make all connections firmly and have the wire clean 
under the binding posts. 

(8) Only a few drops of oil are needed at long intervals, 
don't neglect to oil them, but above all do not drown them with 
oil. 

(9) Examine the brush occasionally and clean off all oil and 
dirt. 

(10) When replacing the magneto on the engine after its 
removal see that the gears are meshed in the former position. 
Best to mark the teeth before removal. 



GAS, OIL AND STEAM ENGINES 253 

(100) High Tension Magnetos. 

The "true" high tension type magneto is complete in itself, 
requiring no jump spark coil nor timer, the high tension cur- 
rent being generated directly in the coils carried by the arma- 
ture. This arrangement reduces the wiring problem to a mini- 
mum, as the only wires required are those leading directly to 
the spark plugs, and one low tension wire connecting the cut- 
out switch used for stopping the engine. 

The armature of this type of magneto carries two independ- 
ent windings, one of a few turns of coarse wire called the pri- 
mary coil, and the other consisting of thousands of turns of 
extremely fine wire calle f d the secondary coil. It is in the latter 




Fig. 105. Single Cylinder High Tension Bosch Magneto. 

coil that the high tension current is generated. The timer is 
connected directly to the armature shaft, and is an integral pttrt 
of the magneto. All primary connections are therefore made 
within the magneto. 

Belts or friction drives cannot be used with this type of 
magneto. 

As there are no vibrators or independent coils used, the spark 
occurs exactly at the instant that the timer operates or breaks 
the primary circuit. It will be noted that the spark is produced 
with this magneto when the' primary circuit is broken by the 
timer, instead of made as is the case with battery coils, or coils 
used with low tension magnetos. There is no lag and conse- 
quently the time of ignition is not affected by variations in the 
engine speed, which requires an advance and retard of the spark 
with batteries and vibrator coils. 



254 GAS, OIL AND STEAM ENGINES 

When used with multiple cylinder engines the high tension 
magneto is provided with a distributor, which connects the high 
tension current with the different cylinders in their proper firing 
order. The timer determines the time at which the spark is 
to occur and the distributor determines the cylinder in which 
the spark is to take place. 

The sparks delivered by the high tension magneto are true 
flames or arcs of intense heat, and exist in the spark gap for an 
appreciable length of time. It is evident that such flames pos- 
sess a much greater igniting value than instantaneous static 
spark delivered by the high tension spark coil used with the bat- 




Fig. 106. Connecticut High Tension Magneto. 

tery or operated by the low tension magneto, and are capable 
of firing much weaker mixtures. 

Like low tension magnetos, the true high tension type may be 
of either the inductor or shuttle wound class. All high tension 
magnetos are positively connected or geared to the engine in 
such a manner that there is a fixed relation between time of the 
current impulse produced by the magneto and the firing posi- 
tion of the engine piston. 

The current is generated on the same principle as in the 
low tension shuttle type; that is, by a coil of wire revolving 
in the magnetic field established by permanent magnets. 



GAS, OIL AND STEAM ENGINES 



255 



During each revolution of the armature, two sparks are pro- 
duced at an angle of 180° from each other. 

The advance and retard of the spark is obtained by means 
of the timing lever which shifts the timer housing back and 
forth which results in the primary current being interrupted 
earlier or later in the revolution of the armature. 

The timing lever can turn through an angle of 40° measured 




Fig. 107. Longitudinal Section Through Bosch High Tension Magneto. 

on the armature spindle, and the angle of advance for multiple 
engines is as follows: 

Advance for 1 cylinder 40° 

Advance for 2 cylinders 40° 

Advance for 3 cylinders 50° 

Advance for 4 cylinders 40° 

Advance for 6 cylinders 27° 
A timer is used with the magneto on a "jump spark" system 
in the same way as with a battery, providing a vibrating coil 
is used. 

In one type of magneto the Connecticut, the coil is part 
of the magneto, and is fastened to the magneto frame. This 
type of magneto uses a non-vibrating coil, and produces but 
a single spark each time the primary circuit is broken by the 
magneto timer. As the timer on this type is driven by the 



256 GAS, OIL AND STEAM ENGINES 

magneto shaft, it is evident that the magneto must be "timed" 
with the engine, or must have its armature shaft connected 
to the shaft of the engine in such a manner that the timer con- 
tact is broken, and the single spark produced at the instant 
that ignition is required in the cylinder. 

Unlike the dynamo, the alternating current magneto can- 
not be used with a storage battery, the alternating current pro- 
ducing no chemical change in the electrodes of the battery. 

The Bosch high tension magneto is a typical high tension 
magneto having the primary and secondary windings wound 
directly on the armature shaft, there being no external sec- 
ondary coil. The end of the primary winding is connected 
to the plate (1) Fig. 107, which conducts the current to the 




Four Cylinder "D4" High Tension Bosch Magneto Showing Distributor. 

platinum screw of the circuit breaker (3). Parts (2) and (3) 
are insulated from the breaker disc (4),- which is in electrical 
contact with the armature core and frame. When the circuit 
breaker contacts are together the primary winding is short 
circuited, and when they are separated the current is broken 
and the spark occurs. The breaker contacts are simply two 
platinum pointed levers that are separated and brought to- 
gether by the action of a cam as they revolve. A condenser 
(8) is provided for the circuit breaker to suppress the spark 
and to increase the rapidity of the "break." 

The. secondary winding of fine wire is a continuation of the 
primary winding, and the secondary is wound directly over the 
primary. The outer end of the secondary connects with the 



GAS, OIL AND STEAM ENGINES 



257 



slip ring (9) on which slides the carbon brush (10), which con- 
ducts the high tension current from the armature. This brush 
is insulated from the frame by the insulation (11). From (10) 
the current is led through the bridge (12) through the carbon 
brush (13) to the distributer brush (15). Metal segments are 
imbedded in the distributor (16), the number of which corre- 
sponds to the number of cylinders. As the brush rotates, it 
makes consecutive contact with each of the segments in turn 
and therefore leads the current to the cylinders in their firing 
order. Wires from the cylinders are connected to sockets that 
in turn connect with the segments. The disc driving the dis- 




Fig. 108. Bosch High Tension Circuit. 

tributor brush (15) is geared from the armature shaft in such 
a way that the armature turns twice for every revolution of the 
distributor, when four cylinders are fired, and three times for 
the distributors once when six cylinders are fired. 

The voltage of the current generated in the secondary coil 
by the rotation of the armature is increased by the interrup- 
tion of the primary circuit caused by the opening of the contact 
breaker. 

At the instant of interruption of the primary circuit the high 
tension spark is produced at the spark plug. 

As the spark must occur in the cylinder of the engine at a 
certain position of the piston, it is necessary that the interrupter 
act at a point corresponding to a definite position of the piston, 
consequently this type of magneto must be driven positively 



258 GAS, OIL AND STEAM ENGINES 

from the motor by means of gears, or directly from the shaft. 

These magnetos run in only one direction. This running 
direction should be given when magneto is ordered, as being 
"clockwise" or "counter-clockwise" when looking at the driving 
end of the magneto. 

The magneto for the single and double cylinder engines has 
no distributor, the high tension current being led directly from 
the armature. 

The circuit diagram of the Bosch four cylinder magneto is 
shown by Fig. 108, the winding and plug connections being 
clearly shown. When connecting the magneto care should be 
taken to have the distributor and plug connections arranged so 
that the cylinders will fire in the proper order. 

(101) Bosch Oscillating High Tension Magneto. 

The oscillating type of magneto is used on slow speed heavy 
duty engines that move too slowly for the ordinary type of 
magneto. In the oscillating type the armature is given a short 
angular swing by the action of a tripping device operated by 
the engine which results in an intense spark at the lowest 
speeds. 

Magneto type "29" is constructed with two powerful steel 
magnets, while magneto type "30" is provided with three; an 
armature of the shuttle type is arranged to oscillate between 
their poleshoes. 

The magneto is actuated by a rotating cam or other suitable 
device, which moves the armature 30° from its normal position 
whenever ignition is required. To permit this movement, a 
trip lever is mounted upon the tapered end of the armature 
shaft, this trip lever being held in a definite position by the 
tension of the spring or springs 1. The trip lever is only sup- 
plied when specially ordered, but each magneto is provided 
with the necessary springs and spring bolts. 

When the trip lever is moved from its normal position by 
the operating mechanism, the springs are extended, and when 
the operating mechanism releases the trip lever, the later re- 
turns the trip lever and armature to their normal position, this 
movement resulting in the production of a sparking current in 
the armature winding. 

The winding of the armature is composed of two parts, one 
being the primary winding, which consists of a few turns of 
heavy wire, and the other the secondary winding, which con- 
sists of many turns of fine wire. 



GAS, OIL AND STEAM ENGINES 259 

The tension of the current produced by the oscillation of 
the armature is increased by closing the primary circuit at a 
certain position in its movement, and then interrupting it by 
means of the breaker. At the moment of the interruption, 
an arc-like spark is formed at the spark plug and ignition occurs. 

On cam shaft (c) two cams are mounted side by side. One 
of these cams (a) is to be used for starting the motor, or for 
the retarded spark position, while the. second (b) is to be used 
for operation, or for the full advance position. These cams 
are mounted on a sleeve, which may be moved longitudinally 
on the shaft, so that the trip lever may be operated by cam 
(a) or cam (b) as desired. The sleeve is caused to rotate with 
the shaft by a key. Between the cam (b) and a fixed collar (f) 
a spiral spring is arranged, which tends to maintain the sleeves 




Fig. 109. Elevation of Bosch Oscillating Magneto for Slow Speed 
Engines. High Tension Type. 

in the position when the cam (b) is in operation. A stop collar 
is also provided to limit the movement of the sleeve beyond this 
full advance position. Over this collar is fitted a hand wheel, 
which, in the position illustrated in the diagram, acts together 
with the collar as a stop. Around the collar is a circular key- 
way, and a brass bolt is located in the hand wheel to lock into 
this keyway when the hand wheel is pushed into the position 
indicated by the dotted lines. This movement of the wheel 
forces the cam sleeve forward, and brings the retarded cam (a) 
into the operating position to permit the engine to be started. 

(102) The Mea High Tension Magneto. 

The low tension winding of the ordinary type of magneto is 
short-circuited by a breaker which opens at certain points of 



260 



GAS, OIL AND STEAM ENGINES 



each revolution with the result that a high voltage is generated 
across the high tension winding at the moment of the break, 
and a spark produced across the spark gap in the cylinder to 
which it is connected. The quality of this spark, or in other 
words the heat value, depends among other factors upon the 
particular position of the armature in relation to the magnetic 
field at the moment the spark is produced. As the armature in 
this type of magneto is in a favorable position for obtaining a 




Fig. 110. Diagram of Oscillating Magneto, Showing Cam and Trigger 

Arrangement. 



spark twice every revolution, two sparks can be obtained per 
revolution. The timing of the spark is accomplished by open- 
ing the breaker earlier or later, by shifting the breaker housing 
naturally with the unavoidable result that if the position of the 
magnetic field remains stationary, the relative position between 
armature and field at the moment of the break must vary. Since, 
however, as explained above, the quality of the spark depends 
upon this relative position, it is apparent that a good spark, 



GAS, OIL AND STEAM ENGINES 



261 



can, with a stationary magnetic field, be produced only at one 
particular timing. 

The result of these conditions are known to everybody 




Fig. 111. Side Elevation of "Mea" Magneto, Showing the Magnets, and 
Cradle in Which the Magneto Swings When Advanced and Retarded. 

familiar with automobiles. They are the difficulty of cranking 
a motor on one of the average high tension magnetos, if the 
spark is fully retarded, and of operating the motor on the mag- 



76 91 IT 




53' 1 12 4 18 100 x 24 

Fig. 112. Longitudinal Section of "Mea" High Tension Magneto. 

neto at very low speed, particularly when it is overloaded, as 
for example, in hill climbing. Attempts have therefore been 
made to obtain the spark, independent of the timing, always at 
the same favorable position of the armature. 



262 GAS, OIL AND STEAM ENGINES 

The distinct innovation and improvement incorporated in the 
Mea magneto consists in bell shaped magnets (Fig. Ill) placed 
horizontally and in the same axis with the armature, instead of 
the customary horse-shoe magnets placed at right angle to the 
armature. 

This at once makes possible and practicable the simultaneous 
advance and retard of magnets and breaker instead of the ad- 
vance and retard of the breaker alone as the magnets may be 
moved to and fro with the breaker housing. It will be seen that 
as a result of this new departure the relative position of arma- 
ture and field at the moment of sparking is absolutely main- 
tained, and the same quality of spark is therefore produced, no 
matter what the timing may be. Furthermore, the range of 
timing, which with the horse-shoe type of magneto is limited 
to 10° or 15° at low speeds (i. e. at speeds at which a retarded 
spark is of value) becomes limited only by the necessity of 
supplying a suitable support for the magnets. With the stand- 
ard types of Mea magnetos described in the following, this 
range varies from about 45° to 70°, but if necessary this range 
can be increased to any amount desired. 

The bell-shaped magnets are fixed to the casing which is 
mounted on a base supplied with the magneto. The timing is 
altered by turning the casing and magnets together on the base. 

Fig. 112 shows a longitudinal section of a four cylinder Mea 
magneto. The armature F with the ball bearings 17-18 rotates 
in the bell-shaped magnets 100, the poles of the magnets being 
on a horizontal line opposite the armature 1. The armature is of 
the ordinary H type iron core wound with a double winding of 
heavy primary and fine secondary wire. On the armature are 
mounted the condenser 12, the high tension collector ring 4, 
and the low tension circuit breaker 26-39. 

The circuit breaker consists of a disc 27 on which are mounted 
the short platinum 33, the other contact point 34 is movable 
and is supported by a spring 30 which is fastened to the in- 
sulated plate 28 mounted on disc 27. Fiber roller 31 in con- 
nection with cam disc 40 which is provided with two cams is 
located inside the breaker. Revolving with the armature the 
roller presses against the spring supported part of the breaker 
whenever it rolls over the two cams which of course is twice 
per revolution. 

Inspection of the breaker points is made easy by an opening 
in the side of the breaker box. The box is closed by a cover 
74 supporting at its centre the carbon holder 47 by means of 



GAS, OIL AND STEAM ENGINES 



26:3 



which the carbon 46 is pressed against screw 24. This latter 
screw connects with one end of the low tension winding while 
the other end is connected to the core of the armature. It 




Magneto of Roberts Motor in Advanced Position. 

will, therefore, be seen that the breaker ordinarily short-circuits 
the low tension winding and that this short-circuit is bioken 
only when the breaker opens; it will also be apparent that when 




112-a. Advance and Retard Mechanism Used in the Roberts Motors. 
The Magneto is Driven by a Helical Gear from the Small Pinion. 
By Shifting the Gear Back and Forth on the Pinion, the Armature 
of the Magneto is Advanced or Retarded in Regard to the Piston 
Position. The Reason for this Change Will be Seen from the 
Cuts by Noting the Position of the Lower Helix. 

the screw 24 is grounded through terminal 50 and the low-ten- 
sion switch to which it is connected, the low-tension winding 



264 GAS, OIL AND STEAM ENGINES 

remains permanently short-circuited, so that the magneto will 
not spark. The entire breaker can be removed by loosening 
screw 24. 

The high tension current is collected from collector ring 4 by 
means of brush 77 and brush holder 76, which are supported by 
a removable cover 91 which also supports the low tension 
grounding brush 78 provided to relieve the ball bearings of all 
current which might be injurious. Cover 91 also carries the 
safety gap 89 which protects the armature from excessive volt- 
ages in case the magneto becomes disconnected from the spark 
plugs. 

The distributor consists of the stationary part 70 and the 
rotating part 60 which is driven from the armature shaft through 
steel and bronze gears 7 and 72. The current reaches this dis- 
tributor from carbon 77 through bridge 84 and carbon 69. It is 
conducted to brushes 68 placed at right angles to each other 
and making contact alternately with four contact plates em- 
bedded in part 70. These plates are connected to contact holes 
in the top of the distributor, into which the terminals of cables 
leading to the different cylinders are placed. 

In the front plate of the magneto is provided a small window, 
behind which appear numbers engraved on the distributor gear 
which correspond to the number of the cylinder the magneto is 
firing. This indicator is of great value as it allows a setting or 
resetting after taking out, without the necessity of opening up 
the magneto to find out where the distributor makes contact. 

The magneto proper is mounted in the base 53 which is 
bolted to the motor frame and the arrangement is such that the 
magneto can be removed frt>m its base by removing the top 
parts 60a and 60b of the two bearings. The variation in timing 
is affected by turning the magneto proper in the stationary base 
which is accomplished by the spark lever connections attached 
to one of the side lugs 88. The spark is advanced by turning 
the magneto opposite to rotation and is retarded by turning it 
with rotation. One cylinder magnetos are similar to the four 
cylinder except that the distributor and gears are omitted. 

(103) The Wico High Tension Igniter. 

The Wico igniter produces a spark similar tc that of the 
conventional high tension magneto except that the heat of the 
spark is independent of the engine speed. In other respects it 
is very different from the types described in the preceding 
pages for its motion is reciprocating instead of being rotary, and 



GAS, OIL AND STEAM ENGINES 265 

because all of the wire is stationary, the only movement being 
that of the iron core that passes through the center of the 
fields. The fact that the spark is of the same intensity at all 
speeds makes this device particularly desirable in starting the 
engine at which time the mixture is always of the poorest 
quality. 
It is very simple, and is without condensers, contact points 




Fig. 113. Wico Igniter. High Tension Reciprocating Type. 

or primary windings, and has no parts that require adjustment. 
The current is generated by the reciprocating movement of 
two soft iron armatures shown as a bar across the bottom of 
the two coils, which move alternately into and out of contact 
with the ends of the soft iron cores. The movement of these 
armatures in the upward direction is produced by the motion of 
the engine and the speed of this movement is, of course, pro- 



266 GAS, OIL AND STEAM ENGINES 

portional to the speed of the engine. The downward move- 
ment, which produces the spark, is caused by the action of a 
spring, is much more rapid than the upward movement and 
entirely independent of the speed of the engine. 

The magnets are made of tungsten steel, shown as two bars 
across the top of the coils, hardened and magnetized and are 
fastened by machine screws to the cast iron pole pieces, which 
serve to carry the magnetic lines of force from the poles of 
the magnets to the soft iron cores. The cores, which fit into 
slots milled in the pole pieces, are laminated or built up of 
thin sheets of soft iron, each sheet being a continuous piece, 
the full length of the core. Each core, extends from just below 
the top armature, down through the pole piece, and coil to just 
above the bottom armature. 

Each armature consists of a number of laminations or sheets 
of soft iron mounted on a spool shaped bushing, which, in turn, 
is loosely fitted onto the squared end of the armature bar. The 
armature bar is supported with a sliding fit in a box shaped 
guide which is fastened in the case. 

On the outer ends of the armature bar are spiral springs held 
in place by cup shaped washers and retaining pins, the combina- 
tion making a self-locking fastening similar to the familiar 
valve spring fastening used almost universally on gas engines. 
These springs bear against the armatures and tend to force 
them against the shoulders of the armature bar. 

The coils each have a simple high tension winding of many 
turns, thoroughly insulated and protected against mechanical 
injury. They are connected together in series by means of a 
metal strip, thus making one continuous winding. In the single 
cylinder igniter, one end of the winding is grounded to the case 
of the igniter, while the other end is connected to the heavily 
insulated lead wire. This lead wire passes out through a stuf- 
fing box, packed with wicking and thoroughly water tight, direct 
to the spark plug in the cylinder. 

In the two cylinder machine no ground connection is used, 
but both ends of the winding are connected to lead wires pass- 
ing out of the case to the spark plugs. 

The action of the igniter is as follows: — As the driving bar, 
through its connection with the engine, is moved downward to 
its limit of travel, carrying the latch with it, the shoulder on 
the side of the latch snaps under the head of the latch block. 
As the motion reverses the latch carries the latch block and ar- 
mature bar upward. The lower armature, being in contact with 



GAS, OIL AND STEAM ENGINES 267 

the stationary cores, cannot rise with the armature bar, but the 
lower armature spring is compressed between its retaining 
washer and the armature, while the bar rises and carries with it 
the upper armature, which bears against the upper shoulders 
on the bar. 

As the driving bar continues its upward motion the upper end 
of the latch meets the lower end of the timing wedge and, as 
the wedge is held stationary by the timing quadrant, a further 
movement of the latch causes it to be pushed aside until the 
shoulder on the latch clears the latch block and releases it. 

As the lower armature spring is at this time exerting a pres- 
sure between the armature bar and cores through the medium 
of the lower armature, the instant the latch block is released, 
the armature bar is quickly pulled downward, carrying the 
upper armature with it. Just before the motion of the upper 
armature is stopped by its coming in contact with the cores, 
the lower shoulders on the armature bar come in contact with 
the lower armature, and, as the bar has acquired considerable 
velocity, its momentum carries the lower armature away from 
the cores against the pressure of the upper armature spring, 
which thus acts as a buffer to gradually stop the movement 
of the armature bar. The armature bar finally settles in a 
central position. 

The timing of the spark is accomplished by releasing the ar- 
mature bar earlier or later in the stroke. This is done by shift- 
ing the position of the eccentric timing quadrant, which in turn 
varies the position of the wedge so that the latch strikes it 
earlier or later in the stroke. The timing quadrant is furnished 
with several notches into one of which the top of the wedge 
rests, thus holding the quadrant in the desired position. 

The motion should preferably be taken from an eccentric on 
the cam shaft of a single cylinder four cycle engine, or the 
crank shaft of a single cylinder two cycle or a two cylinder 
four cycle engine. On a two cylinder four cycle engine, it is 
sometimes more convenient to drive the igniter from the cam 
shaft, using a two throw cam to produce the required number 
of sparks. In this case the shape of the cam should be such as 
to duplicate the motion of the eccentric. That is, it should start 
the driving bar slowly from its lower position, move it most 
rapidly at mid stroke and bring it to rest gradually at the upper 
end of the stroke, exactly as is done by the eccentric motion. 

When an eccentric is already on the engine the motion may 
be taken from it to an igniter with a driving bar through a 



268 



GAS, OIL AND STEAM ENGINES 



properly proportioned lever that will give the required length 
of stroke. Where a plunger pump is used on the engine the 
motion can usually be taken from the pump rod. Where an 
eccentric has to be provided especially for the igniter, the driv- 
ing bar is generally used with its roller running on the eccentric. 

(104) Starting On Magneto Spark. 

A four-cylinder engine in good condition will come to rest 
with the pistons approximately midway on the stroke and bal- 
anced between the compression of the compressing cylinder and 
of the power cylinder. When the cylinders of such an engine are 
charged with a proper mixture, the engine will start by the igni- 







.. ....... .. . ; 


l^qB-'H^TNTERRUPTER 

f4Kffm^ ^' ' spring 


• SCREW Hi 


nfH* ^^ 


l0CK ~fii 

NUT 


j» £&W&g& B*sS3 


^tfrrjffi 


pL>^B-PLATiNUM' SCREW 

il^^*Bmvf*™^ LEVER 






x^jgWd 


UMm ■ TIMING CONTROL 

m Am 

HhsTEEL SEGMENT 



Fig. 114. Bosch Dual System. 

tion of the mixture contained in the compressing cylinder, for 
the pressure produced by the ignited gas will be sufficient to 
rotate the crankshaft. 

It is essential, for the ignition system to be so arranged that 
a spark can be produced at any point in the piston travel, and 
in this the Bosch dual, duplex and two independent systems are 
successful. 

The Bosch dual system, Fig. 114, is part of the equipment of 
many of the cars and engines marketed, and is composed of 
two separate and distinct ignition systems, one supplying igni- 
tion by direct high-tension magneto, and the other by a battery 
and high-tension coil. These two systems consist in reality of 
but two main parts; the dual magneto, incorporating a separate 
battery timer, and the single unit dual coil with its battery. 
The sparking current from either battery or magneto is brought 



GAS, OIL AND STEAM ENGINES 



269 



to the magneto distributor, so that the only parts used in com- 
mon are the distributor and the spark plugs; the common use 
of the latter for both magneto and battery systems is cause for 
the popularity of the dual system for motors having provision 
for only one set of plugs. 

In both the magneto and the battery sides the spark is pro- 
duced on the breaking of the circuit, and the coil is so arranged 
that by pressing a button when the switch is in the battery 
position, an intense vibrator spark is produced in the cylinder 
during that period when the circuit breaker is open, which will 
be the case during the first three-fourths of the power stroke. 
The current is transmitted to the distributor and passes through 
the spark plug of the cylinder that is on the power stroke. 



BATTERY TIMER 








TIMING \ 
CONTROL^ \ 

arm ^^TSSRa 


Js^w^ "' """■'" 




H-JNTERRUPTER 

Br 1 'adjust meat 


( 


;^*' J 'j' 




M SHORT '. 

-CIRCUITING 
TERMINAL 








) 


• \ \ 1 

BATTERY \ j 

CONNECTION \| 

\ 






B TfMiNG 
M CONTROL' 
m ■ ARM 




V>H€R ADJUSTMENT 


K.PIA" 


rmxm POINTS ; 



Fig. 115. Bosch Duplex Breaker. 

Should the engine come to a stop in such a position that the 
battery timer is closed, it will not be possible to produce a 
vibrator spark by the pressing of the button, but the releasing 
of the button will produce a single contact spark that will ignite 
the mixture and thus start the engine. 

Thus if the engine should stop in some odd position, and 
the spark is produced when the piston is slightly before top 
center, for instance, there will be a slight reverse impulse which 
will bring another cylinder on the power stroke and into the 
ignition circuit. The engine will thereupon take up its cycle 
in the proper direction. 

In the Bosch duplex system the .coil is in series with the 
magneto armature, but the spark is produced under the same 
condition, that is, on the breaking of the circuit. In conse- 
quence the Bosch duplex system will permit the production 



270 



GAS, OIL AND STEAM ENGINES 



of a spark during the first three-quarters of the power stroke 
by the pressing of the push button set on the switch plate. 

The Bosch two independent system is composed of a separate 
Bosch battery system and a separate Bosch magneto. Although 
the operation of the coil is somewhat similar to that of the 




The Herz High Tension Magneto in Which the Magnets are Built up of Thin 
Steel Plates Without Pole Pieces (Four Cylinder Type). 

dual system, the nature of the battery system is such as to re- 
quire arrangements for two separate sets of spark plugs. The 
coil is not unlike that supplied with the dual system in that by 
pressing a button located on the switch plate a series of in- 
tense sparks may be produced in the cylinder at all advanta- 
geous points of the power stroke. 



CHAPTER IX 
CARBURETORS 

(105) Principles of Carburetion. 

The carburetor is a device for converting volatile liquid fuels, 
such as gasoline, alcohol, kerosene, etc., into an explosive vapor. 
Besides vaporizing the liquid, the carburetor also controls the 
proportion of the fuel to the air required for its combustion. 
The mixture produced by the carburetor must be a uniform gas 
and not a simple spray to accomplish the best results for com- 
plete and instantaneous combustion. Proper combustion can- 
not be attained with any of the fuel in a liquid state as all 
of the fuel contained in a liquid particle cannot come into con-* 
tact with the consuming air. It is of the utmost importance 
to have the air and fuel in correct proportions so that the fuel 
may be completely consumed without danger of interfering 
with the ignition by an excess of air. 

With few exceptions modern gasoline carburetors are 
of the nozzle type in which the liquid is broken up into an 
extremely fine subdivided state by the suction of the engine 
piston. This fine spray is then fully vaporized or gasified by 
the heat drawn from the surrounding intake air that is drawn 
through the carburetor and into the cylinder on the suction 
stroke. Owing to the low grade fuels now on the market and 
to the constantly varying atmospheric conditions it is seldom 
possible to obtain a perfect vapor in the correct proportions, 
and for this reason much heat is lost that would be available 
were the mixture perfect. 

Carburetors for automobiles and boats vary in detail from 
those used on stationary engines due principally to the differ- 
ence in matters of speed. A stationary engine runs at a con- 
stant speed which makes adjustment comparatively easy, while 
automobile engines have a wide range of speeds and loads mak- 
ing it very difficult to maintain the correct mixture at all points 
in the range. The difference in the fuel and air adjustments 
for varying of speeds marks the principal difference between 
stationary and automobile carburetors. There are many types 

271 



272 



GAS, OIL AND STEAM ENGINES 



of successful carburetors on the market, so many in fact that we 
have room for the description of only three or fo.ur of the 
most prominent, but we will say that the well known car- 
buretors are based on the same principles and differ only in 
matters of detail. 

A cross-sectional view of the well known Schebler Type D 
carburetor is shown by Fig. 116, and is of the type commonly 
used on automobile motors and boats. 

(106) Schebler Carburetor. 

The carburetor is connected to the intake of the engine by 

MODEL "D" 




Fig. 116. Cross-Section Through Type "D" Schebler Carburetor. 

pipe screwed into the opening R, the gas passing from the car- 
buretor to the engine through this op.ening. 

D is the spray nozzle which opens into the float chamber B, 
the opening of the nozzle being regulated by needle valve E 
which controls the quantity of gasoline flowing into the mixing 
chamber C. 

On the suction stroke of the engine, air is drawn through the 
upper left hand opening, past the partially open auxiliary air 



GAS, OIL AND STEAM ENGINES 273 

valve A, past the needle valve D, through the mixing chamber 
C, and into the engine through R. 

The suction of the engine produces a partial vacuum in the 
mixing chamber C which causes the gasoline to issue from the 
nozzle D, in the form of a fine spray which is taken up by the 
air passing through the passage H, and is taken into the engine 
through R, thoroughly mixed. The amount of mixture entering 
the engine, and consequently the engine speed is regulated by 
the throttle valve K, operated by the lever P. 

In order that the amount of spray given by the nozzle D be 
constant it is necessary that the level, or height of the gasoline 
in the nozzle be constant. The level is maintained by means 
of the float F, which opens, or closes the gasoline supply valve 
H, opening it and allowing gasoline to enter when the level is 
low, and closing the valve when the level is high. 

The carburetor is connected to the gasoline supply tank, by 
pipe connected to the inlet G, through which the gasoline flows 
into the float chamber B. The float chamber carries a small 
amount of gasoline on which the float F rests. The richness 
of the mixture is controlled by opening or closing the nozzle 
needle valve E, which passes through the center of the nozzle D. 

The float F surrounds the nozzle in order to keep the level of 
the liquid constant when the carburetor is tilted out of the 
horizontal by climbing hills, or by the rocking of the boat 
when used on a marine engine. 

A drain cock T is placed at the bottom of the float chamber 
for the purpose of removing any water, or sediment that may 
collect in the bottom of the float chamber. 

At low speeds, the auxiliary air valve A lies tight on its seat, 
allowing a constant opening for the incoming air through the 
space shown at the bottom of the valve. 

When the speed of the engine is much increased, the vacuum 
is increased in the mixing chamber C, which overcomes the 
tension of the air valve spring O and allows the valve to open 
and admit more air to the mixing chamber. The action of the 
auxiliary air valve keeps the mixture uniform at different en- 
gine speeds, as it tends to keep the vacuum constant in the mix- 
ing chamber. 

When the engine speed increases, the flow of gasoline is 
greater, and consequently more air will be required to burn it; 
this additional air is furnished by the automatic action of the 
valve, and when once adjusted, compensates accurately for the 
different engine speeds. 



274 GAS, OIL AND STEAM ENGINES 

The gasoline is generally supplied by a tank elevated at least 
six inches above the level of the fluid in the float chamber; al- 
though in some cases the gasoline is supplied by air pressure on 
a tank situated below the level of the carburetor. 

In some types of Schebler carburetors, the float chamber B 
is surrounded by a water jacket that is supplied with hot water 
from the cylinder jackets of the engine. This keeps the gasoline 
warm so that it evaporates readily under any atmospheric con- 
ditions. 

The quantity of air admitted to the carburetor is controlled 
by an air valve shown in the air intake by the dotted lines. 
This is adjusted by hand for a particular engine and is seldom 
touched afterward. 

When starting the engine it is necessary to have a very rich 
mixture for the first few revolutions, this mixture being ob- 
tained by "flooding" the carburetor. 

On the Schebler carburetor the mixing chamber is flooded by 
depressing the "tickler" or flushing pin V. 

(107) Two Cycle Carburetors. 

Nearly any type of carburetor can be used on a two port, two 
stroke, cycle engine providing a check valve is placed between 
the crank case and carburetor to prevent the crank-case com- 
pression from forcing its contents back through the inlet pas- 
sages. A great many manufacturers make special carburetors 
for two stroke motors that have the check valve built into the 
carburetor itself. With three port two stroke cycle engines a 
check valve is not necessary as the piston in this type of engine 
performs this duty. 

In that class of vaporizers known as mixing valves, the valve 
that controls the flow of gasoline blocks the air passage in such 
a way that an additional check valve is not necessary. 

(108) Kingston Carburetors. 

The Kingston Carburetor shown by Fig. 117 differs from the 
Schebler in many details, the principal difference being in the 
construction of the spray nozzle and the construction of the 
auxiliary air valve. The throttle valve E controlls the exit of 
the mixture through the engine connection C which is an ex- * 
tension of the mixing chamber. The spray nozzle J which is 
surrounded by a hood or tube is controlled by the needle valve 
A which is threaded into the top of the mixing chamber, this 



GAS, OIL AND STEAM ENGINES 275 

latter adjustment being locked into place by a button head 
screw and a slot in the casting. 

Surrounding the nozzle tube or hood is a curved restriction 
in the air intake passage, is known as a Venturi tube, which 
insures a constant relation between the air and fuel supplies. 
As the action of the Venturi tube is rather complicated, it will 
not be taken up in detail. Air is supplied to the Venturi 
passage through the intake (D). An annular float (K) sur- 
rounds the mixing chamber that acts on the gasoline sup- 
ply valve (I) through a short lever arm. This valve is acces- 
sible for cleaning on the removal of the cap H that covers the 




Fig. 117. Cross-Section Through Kingston Carburetor Showing Balls 
Used for Auxiliary Air Valves. 

v'alve chamber. Gasoline enters the float chamber through 
the fuel pipe G, and enters the spray nozzle through the two 
ports in the base of the mixing chamber. 

The auxiliary air valve is a particularly novel feature of this 
carburetor, as no springs nor disc valves are used in its con- 
struction. Five balls (M) of different weights and sizes act 
as air valves, the balls covering the inlet ports (L) under nor- 
mal operation. As the speed increases, the balls are lifted off 
their seats in order of their weight or size by the increase in 



276 GAS, OIL AND STEAM ENGINES 

suction. With a slight increase of suction, the lightest ball cov- 
ering the smallest hole is lifted first, a further increase in suc- 
tion lifts the next largest ball which still further increases the 
auxiliary air intake, and so on until at the highest speed all 
of the balls are off their seats. Access tD the ball valves is had 
through the valve caps (N). The constant supply inlet is 
circular and may be set at any desired angle, as can the float 
chamber and gasoline supply connection. Control and adjust- 
ment are entirely by the needle valve. 

(109) The Feps Carburetor. 

The Feps carburetor has the main needle valve surrounded 
by a Venturi chamber as in the preceding case, the needle valve 
adjustment being made through a lever on the left of the mix- 
ing chamber. An auxiliary nozzle directly under the auxiliary 
air valve at the right, connects with the float chamber and 
furnishes an additional mixture of gasoline and air for hill 
climbing and high speed work when the leather faced auxiliary 
air valve lifts from its seat. The adjustment for this auxiliary 
jet is shown at the right of the air valve chamber. 

For intermediate speeds, the air valve alone is in action. No 
controlling springs are used on the air valve which insures posi- 
tive action and sensitive control of the air. A float surrounding 
the Venturi tube controls the fuel valve through the usual lever 
arm. A wire gauze strainer placed in the fuel chamber to the 
left prevents dirt and water from being drawn into the nozzle, 
and as this strainer easily removed it is a simple matter to clean 
and prevent the troubles due to dirty fuel. 

By closing the upper valve in the vertical engine connection 
the vacuum is increased in the manifold when starting the en- 
gine. This increase of vacuum draws gasoline from the float 
chamber and primes the engine making the engine easy to start 
in cold weather. The tube through which the gasoline is drawn 
for priming is the small crooked tube bending over the float and 
terminating above the starting valve. Below this valve is the 
throttle valve which controls the mixture in the ordinary man- 
ner. The adjustment for intermediate speeds is made by the 
center knurled thumb-screw shown over the air valve chamber 
which controls the travel of auxiliary air valve. In effect this is 
a double carburetor, one jet for high speed and one for low. 



GAS, OIL AND STEAM ENGINES 



277 



(111) Gasoline Strainers. 

Much trouble is caused in carburetors by dirt, water and 
sediment, collecting in the small passages and obstructing the 
flow of the gasoline. 

The purpose of the gasoline strainer is to prevent any water 




Fig. 119. ^ The Excelsior Carburetor in Which the Air is Regulated by a Ball 
which Lies in the Tapering Venturi Tube. An Increase of Suction 
Lifts the Ball and Allows More Air to Pass. 

or foreign matter from being carried into the carburetor, and 
this device should be used on every engine if the owner wishes 
to be free from carburetor troubles. 

(112) Installing Gasoline Carburetors. 

(1) Use brass or copper pipe from the tank to carburetor if 
possible to avoid trouble from dirt and flakes of rust. 

(2) When installing a gasoline tank be sure that the bottom 
of the tank is at least six inches above the carburetor to insure 
a good flow. 



278 GAS, OIL AND STEAM ENGINES 

(3) The tank should be provided with an air vent hole, or 
the gasoline will not flow because of the vacuum in the top of 
the tank. 

(4) All tanks should be provided with a drain cock at the 
lowest point so that water and dirt may be easily removed. 

(5) Clean out the tank thoroughly before filling with gaso- 
line to avoid clogged carburetors. 

(6) Pipes from the tank to carburetor should never be placed 
near exhaust pipes or hot surfaces for the gasoline vapor may 
prevent the feeding of gasoline. 

(7) Clean out pipes before using. 

(8) If common threaded pipe joints are used on the gasoline 
piping, use common soap in place of red lead. 

(113) Installing the Carburetor. 

The carburetor should be placed as near to the cylinder as 
possible, the shorter the pipe, the less the amount of vapor 
condensed in the manifold. With multi-cylinder engines the 
carburetor should be so situated, that is, an equal distance from 
each cylinder, so that each cylinder will inhale an equal amount 
of vapor. 

The intake opening of the pipe should be placed near one of 
the cylinders, or draw warm air off the surface of the exhaust 
pipe in order that gasoline will evaporate readily in cold weather, 
and form a uniform mixture at varying temperatures. 

Great care should be taken to prevent any air leaks in the 
carburetor, or intake manifold connections, as a small leak will 
greatly reduce the strength of the mixture and cause irregular 
running. Always use a gasket between the valves of a flanged 
connection and keep the bolts tight. If a brazed sheet brass 
manifold is used, look out for cracks in the brazing. 

Leaks may be detected in the connections by spurting a little 
water on the joints, and turning the engine over on the suction 
stroke. If the water is sucked in the leaks should be repaired 
at once. Make sure when placing gaskets, that the gasket does 
not obstruct the opening in the pipe, and that it is securely 
fastened so that it is not drawn in by the suction. 

Never allow the carburetor to support any weight, as the shell 
is easily sprung which will result in leaking needle valves. 

CARBURETOR ADJUSTMENT. When adjusting the car- 
buretor of multiple cylinder engine, it is advisable to open 
the muffler cutout in order that the character of the exhaust 
may be seen or heard. With the muffler open, the color of 



GAS, OIL AND STEAM ENGINES 279 

the exhaust should be noted. With a PURPLE flame you may 
be sure that the adjustment is nearly correct for that load 
and speed; a yellow flame indicates too much air; a thin blue 
flame too much gasoline, and is not the best for power. 

Before starting for the adjustment test, try the compression, 
and the spark. If the compression is poor, try the effects of a 
little oil on the piston, which may be introduced into the cyl- 
inder through the priming cup. It will be well to dilute the oil 
to about one-half with kerosene. After all trouble with all the 
parts are clear, you may start the engine. 

Turn on the gasoline at the tank, and after standing a moment 
see whether there is any dripping at the carburetor, if .there is, 
the trouble will probably be due to a leaky float, dirt in the 
float valve, or to poor float adjustment. Locate the leak and 
remedy it before proceeding further. Dirt on the seat of the 
needle valve may sometimes be removed by "flooding" the car- 
buretor, which is done by holding down the "tickler" lever for 
a few seconds, causing the gasoline to overflow, and wash out 
the dirt. 

If the motor has been standing for a time it would be well to 
"prime" the motor by admitting a little gasoline into the cyl- 
inder through the priming cup, or by pushing the tickler a 
couple of times so as to slightly flood the carburetor. 

Now turn on the spark and turn over the engine for the start, 
taking care that the throttle is just a little farther open than its 
fully closed position. If the engine takes a few explosions and 
stops, you will find the nozzle, or that some part of the fuel pip- 
ing is clogged which will stop the engine. If the motor grad- 
usually slows down, and stops, with BLACK SMOKE issuing 
from the end of the exhaust pipe, or MISFIRES badly, the mix- 
ture is TOO RICH, and should be reduced by cutting down the 
gasoline supply by means of the needle valve adjusting screw. 
If it stops quickly, with a BACKFIRE, or explosion at the 
supply of gasoline should be INCREASED by adjusting the 
mouth of the carburetor, the mixture is TOO LEAN, and the 
needle vaVe, 

In all cases be sure that the auxiliary valves are closed when 
the engine is running slowly, with the throttle closed, as in the 
above test. If they are open at low speed, the mixture will be 
weakened and the test will be of no avail. 

After adjusting the needle valve as above until the engine is 
running (with throttle in the same partially closed position), 
turn the valve slowly in one direction or the other until the 



280 GAS, OIL AND STEAM ENGINES 

motor seems to be running at its best. During the above tests 
the spark should be left retarded throughout the adjustment, 
and the throttle should not be moved. 

The carburetor should now be tested for high speed adjust- 
ment, by opening the throttle wide (spark % advanced), and 
observing the action of the motor. If the engine back-fires 
through the carburetor at high speed, it indicates that the mix- 
ture is too weak which may be due to the auxiliary air valve 
spring tension being too weak and allowing an excess of air to 
be admitted. Increase the tension of the spring, and if this does 
not remedy matters, admit a little more fuel to strengthen the 
mixture by means of the needle valve adjustment. Do not touch 
the needle valve if you can possibly avoid it, or the high-speed 
adjustment, as the fuel adjustment will be disturbed for low 
speed. 

If the engine misfires, with loud reports at the exhaust, does 
not run smoothly, or emits clouds of black smoke at high speed, 
the engine is not receiving enough air in the auxiliary air valve, 
consequently the tension of the spring should be reduced. 

Back firing .through the carburetor denotes a weak mixture. 

Trouble in cold weather may be caused either by slow evapo- 
ration of the gasoline, or by water in the fuel that freezes and ob- 
structs the piping or nozzle. In cold weather a higher gravity 
of gasoline should be used than in summer, as it evaporates 
more readily, and therefore forms a combustible gas the rate 
at lower temperatures. 

To increase the rate of evaporation of the gasoline, it should 
be placed in a bottle and held in hot water for a time before 
pouring it into the carburetor or tank, or the air inlet warmed 
with a torch. 

The cylinder water jacket should always be filled with hot 
water before trying to start the engine, and will prevent the gas 
from condensing on the cold walls of the cylinder. Often good 
results may be had by wrapping a cloth or towel around the 
carburetor, that has been dipped in hot water. 

The cylinder of an air-cooled engine may be warmed by gently 
applying the heat of a torch to the ribs, or by wrapping hot 
cloths about it. 

The tank, piping, and carburetor should be drained more 
frequently in cold weather than in hot, to prevent any accumu- 
lation of water from freezing, and stopping the fuel supply. A 
gasoline strainer should always be supplied on the fuel line, and 
should be regularly drained. 

The motor may often be made to start in cold weather by 



GAS, OIL AND STEAM ENGINES 281 

cutting out the spark, and cranking the engine two or three 
revolutions with the throttle wide open. The throttle should 
now be closed within % of its fully closed position, the ignition 
current turned on, and the engine cranked for starting. This 
system will very seldom fail of success at the first attempt. 

Carburetor flooding is shown by the dripping of gasoline 
from the carburetor, and which results in too much gasoline in 
the mixture. Flooding may be caused by dirt accumulating 
under float valve, by a leaking float (Copper Float), by Water 
Logged Float (Shellac worn off Cork Float), by float adjust- 
ment causing too high a level of gasoline, by leaking float valve, 
by cutting out ignition when engine is running full speed, by 
rust or corrosion sticking float valve lever, by float binding in 
chamber, by float being out of the horizontal, by float valve 
binding in guide, by excessive pressure on gasoline, or by tickler 
lever held against float continuously. 

Dirt accumulated under float valve may sometimes be flushed 
out by depressing tickler lever several times; if this does not 
suffice, the cap over the valve must be removed, and the orifice 
cleaned by wiping with a cloth. 

LEAKING FLOAT VALVES should be reground with 
ground glass or very fine sand; never use emery as the par- 
ticles will become imbedded in the metal, which will be the 
cause of worse leaks. 

Should the shellac be worn off of a cork float allowing the 
gasoline to penetrate the pores of the cork, a new float should 
be installed, as it is a doubtful policy for owner to give the 
float an additional coat of shellac. 

MISFIRING AT LOW SPEED. If the carburetor cannot 
be adjusted to run evenly on low speed after making all pos- 
sible adjustments with the needle valve, the trouble is prob- 
ably due to air leaks between the carburetor and engine, caused 
by broken gaskets, cracked brazing in the intake manifold, or 
by leaks around the valve stem diluting the mixture. 

INCORRECT VALVE TIMING will cause missing, espe- 
cially on multiple cylinder engines, as the carburetor cannot 
furnish mixture to several cylinders that have different indi- 
vidual timing. Look for air leaks around the spark edge open- 
ings, and be sure that all valves seat gas tight. Always be 
sure that the auxiliary air valve remains closed at low speeds, 
as a valve that opens at too low a speed will surely cause mis- 
firing as it dilutes the mixture. 

MISSING in one cylinder may be caused by an air leak in 
that cylinder. 



282 GAS, OIL AND STEAM ENGINES 

WATER in gasoline will cause misfiiing, especially in freez- 
ing weather, as it obstructs the flow of fuel to the carburetor. 
The carburetor and tank should be drained at regular inter- 
vals, and if possible, a strainer should be introduced in the 
gasoline line. 

CLOGGED NOZZLE. Particles of loose dirt in the nozzle 
will occasion an intermittent flow of gasoline that will result 
in misfiring. The nozzle should be cleaned with a small wire 
run back and forth throughout the opening. 

CLOGGED AIR VENT in the float chamber will change the 
level of the fuel, and will either "starve" the engine, or flood 
the carburetor. The air in the float chamber is a very small 
hole, and is likely to clog. 

HOT FUEL PIPE. If the fuel pipe that connects the tank 
with the carburetor, becomes hot, due to its proximity to the 
exhaust pipe of cylinders, vapor will be formed in the pipe 
that will interfere with the flow of fuel. 

DIRT UNDER AUXILIARY AIR VALVE will prevent 
the valve from seating properly, causing the engine to misfire 
at low speed. 

CRACKS OR LEAKS in intake pipe or gaskets will cause 
intermittent leaks of air and spasms of misfiring. Old cracks 
that have been brazed will sometimes open and close alter- 
nately causing baffling cases of spasmodic misfiring. 

DIRT IN AIR INTAKE will change the air ratio, and the 
increased suction will cause a greater flow of gasoline. Do not 
place the end of the inlet pipe in a dusty place, nor where oil 
can be splashed into it by the engine. Clean out periodically. 

"LOADING UP" of the inlet piping in cold weather on 
light load is caused by the mixture condensing in the intake 
pipe. The only remedy is to keep the piping warm, or to 
heat the inlet air. 

CLOGGED OVERFLOW PIPE, with engines equipped 
with pump supply will cause flooding, as the fuel does not 
return rapidly enough to the tank. 

(114) Kerosene Vaporizer for Motorcycles. 

An ingenious vaporizing device has been designed for the 
use of kerosene as a fuel for motorcycle engines, by the M. G. 
and G. Motor Patents Syndicate, Ltd., England, is described in 
Motor Cycling. The device consists of a comminuter, or vapor- 
izer, which screws into the sparkling-plug hole in the cylinder, 
the plug being transferred to an aperture in the vaporizer, a 



GAS, OIL AND STEAM ENGINES 283 

feeder for regulating the supply of fuel to the vaporizer, and a 
throttle and air barrel, or mixing chamber, for the purpose of 
proportioning the amount of air and gas supplied to the en- 
gine, and for controlling the speed of the machine as in an 
ordinary carburetor. 

The feeder receives the fuel — in this case kerosene — although 
any heavy oil can be used with almost equally good results. 
The feeder answers a purpose similar to the ordinary float 
chamber of the carburetor, i. e., to regulate the amount of kero- 
sene it is required to pass through the vaporizer. It consists 
of a small chamber mounted upon the end of a pipe leading to 
the vaporizer. Kerosene is fed to this device by a copper pipe 
from the tank, and enters at the lowest point through a 3/16- 
inch hole or jet. This is covered by a small valve, operated 
by engine suction. The lift of this valve can be adjusted by the 
insertion of washers to suit any particular size of engine, just 
as one would use various size jets to suit either a large or small 
engine. One of the greatest advantages of the device lies in 
the size of this aperture or jet, inasmuch as it cannot possibly 
choke up with grit, and even water will pass through and not 
stop the operation of the carburetor. At the top of the feeder 
is an air hole, which admits just sufficient air to pass the kero- 
sene through the vaporizer, the reason for this being that the 
heat of the vaporizer shall only act upon the fuel, the mixture 
afterwards being balanced by air being admitted through the 
mixing chamber. 

After the kerosene leaves the feeder it passes through a pipe 
to the vaporizer. This consists of a gunmetal body with cool- 
ing ribs cast on the outside, whilst through the center runs a 
thin copper tube of 5^-inch diameter and only 20 gauge, which 
would really melt during the heat of combustion were it not 
for the fact of the fuel passing through it. The heat derived 
from this formation of vaporizer is approximately 1,000 degrees 
Fahr. Inside the central tube is a strip-steel spiral, which serves 
the double purpose of giving a centrifugal motion to the fuel, 
and at the same time forming a supporter for the tube, prevent- 
ing it crushing under the force of the explosions. It is, of 
course, understood that the inside of the feeding tube is en- 
tirely isolated from the combustion chamber. The sparking 
plug is screwed into the wall of the vaporizer, which is now 
really an extension of the combustion chamber. 

Obviously this slightly reduces the compression of the en- 
gine, which, however, is a necessary feature when kerosene is 



284 



GAS, OIL AND STEAM ENGINES 



used as a fuel. After passing through this device the kerosene 
is thoroughly vaporized, and the vapor is led through a flexible 
pipe to the throttle chamber; this taking the place of an ordinary 
carburetor and being fitted to the induction pipe. 

There are two slides, operated by Bowden levers from the 
handle-bar, one being for the main air intake and the other for 
the gas. 

Undoubtedly the greatest claim for this vaporizer is the fact 
that practically no carbon deposit forms upon the inside of the 




Fig. 121-a. The English Aster Electric Lighting Unit. 

cylinder or on the piston. What little deposit is formed takes 
the shape of small, soft flakes, which, instead of adhering to the 
cylinder walls, break away before they have attained any size 
and are blown through the exhaust valve. Altogether, this de- 
vice seems to have finally solved the problem of using kerosene 
as a fuel on air-cooled engines, especially if the carbon deposit 
difficulty has been finally overcome. % 

The device was fitted to a 2>y 2 h. p. Matchless with a White 
and Poppe engine. In order to start up, a small gasoline tank, 
holding about one half-pint of gasoline, is fitted under the 
main tank and communicates with the feeder. Half a minute 
is all that is necessary running on gasoline, when the kerosene 
can be turned on. The machine would fire at a walking pace, 
and could also be accelerated up to 55 m.p.h. 



CHAPTER X 
LUBRICATION 

(116) General Nates on Lubrication. 

No matter how carefully the surface of a shaft or bearing 
may be finished, there always remains a slight roughness or burr 
of metal, which although of microscopic proportions is produc- 
tive of friction or wear. Each minute projection of metal on a 
dry shaft acts exactly as a lathe tool, when the shaft revolves 
in cutting a groove in the stationary bearing. Since there are 
a multitude of these projections in a journal, the wear would 
be very rapid, and would in a short time completely destroy 
either the shaft or bearing, no matter how highly finished in 
the beginning. 

When lubricating oil is introduced into a bearing it imme- 
diately covers the rubbing surface, and as the oil has a con- 
siderable resistance to being deformed, or is "stiff," it separates 
the surface of the shaft from that of the bearing for a distance 
equal to the thickness of the oil film. With ordinary lubricants 
this distance is more than enough to raise the irregularities of 
the shaft out of engagement with those of the bearing. This 
property of "stiffness" in the oil is known as "viscosity." The 
value of viscosity varies greatly with different grades of oil, 
and also with the temperature with the result that the allowable 
pressure on the oil per square inch also varies. With oils of 
low viscosity a small pressure per square inch on the bearing 
will squeeze it out, and allow the two metallic surfaces to come 
against into contact, causing wear and friction, while an oil of 
greater viscosity will successfully resist the pressure. 

The life and satisfactory operation of the engine depends al- 
most entirely upon the lubricant and the devices that apply it 
to the bearings. Excessive wear and change in the adjust- 
ments are nearly always the result of defective lubricating de- 
vices or a poor lubricant. The principal lubricants are: 

(1) Solid lubricants such as graphite, soapstone, or mica. 

(2) Semi-solid lubricants such as vaseline, tallow, and soap 

285 



286 GAS, OIL AND STEAM ENGINES 

emulsions, or greases compounded of animal fats, vegetable "and 
mineral oils; and 

(3) Liquid lubricants, such as sperm oil, or one of the prod- 
ucts of petroleum, the latter medium being the class of lubri- 
cant most suitable for internal combustion engines, owing to its 
combining the qualities of a high flash-point with a compara- 
tive freedom from either acidity or causticity. 

Oils of animal or vegetable origin should never be used 
with gas engine as the high temperatures encountered will 
char and render them useless. Tallow and lard oil are especially 
to be avoided, at least in a pure state. 

In the cylinder only the best grade of GAS ENGINE cyl- 
inder oil should be used, which according to different makers 
has a flash point ranging from 500 to 700 degrees. Using cheap 
oil in the cylinder is an expensive luxury. In general, the oils 
having the highest flash points have also the objectionable ten- 
dency of causing carbon desposits in the combustion chamber 
and rings which is productive of preignition and compression 
leakage. The lower flash oils have a tendency to vaporize and 
to carry off with the exhaust which will leave the walls insuffi- 
ciently lubricated unless an excessive amount is fed to the cyl- 
inder. By starting with samples of well known brands rec- 
ommended by the builder of the engine it will be an easy mat- 
ter to find which is the cheapest and gives the best results. 
In figuring the cost of oil do not take the cost per gallon as a 
basis, but the cost for so many hours of running,' or better yet 
the number of horse-power hours. Unless you are fond of buy- 
ing replacements and new parts do not stint on the oil supply. 

On the other hand, an excess of oil should be avoided as 
this means not only a waste of oil through the exhaust pipe, 
but trouble with carbon deposits and ignition troubles as well. 
Foul igniters, misfiring, and stuck piston rings are the inevitable 
result of a flood of lubricating oil. When a whitish yellow 
cloud of smoke appears at the end of the exhaust pipe, cut 
down the oil feed. The exhaust should be colorless and prac- 
tically odorless. 

Too much oil cannot be fed to the main bearings of the crank 
shaft if the waste oil is caught, filtered and returned to the 
bearings by a circulating system, for the flood of oil not only 
insures ample lubrication but removes the heat generated as 
well. The bearings require a much lighter oil, of a lower 
fire test than the cylinder oil. It is evident that its viscosity 
is a most important element, as it determines the allowable 



GAS, OIL AND STEAM ENGINES 287 

pressure on the shaft. The viscosity of an oil varies with the 
temperature and is greatly reduced at cylinder heat. A com- 
parative test of the viscosity or load bearing qualities of an oil 
may be made by making bubbles with it by means of a clay 
pipe; the larger the bubble, the higher the viscosity of the oil. 

Different sizes of bearings, and bearing pressures, call for oils 
of different viscosities, and consequently an oil that would be 
suitable for one engine would not answer for another; heavy 
bodied oils being used for heavy bearing pressures, and light 
thin oil for small high speed bearings. The best way to deter- 
mine the value of an oil for a particular shaft bearing is by 
experiment, attention being paid to its adaptability for the 
feeding devices used. 

The compression attained in a gas engine cylinder depends to 
a certain extent upon the body of the cylinder oil, for many 
engines that leak compression past the rings with thin oil will 
work satisfactorily with a heavy viscuous oil that clings tightly 
to the surfaces. An engine will often lose compression when 
an oil of poor quality is used. 

Air cooled engine cylinders require an oil of heavier body 
than water cooled because of the higher temperature of the 
cylinder walls. Gum and sticky residue are usually formed by 
animal oils or adulterants added to the numeral oil base. Oils 
containing free acids should be avoided as they not only cor- 
rode and etch the bearing, but also clog the oil pipes or feeds 
with the products of the corrosion. 

Free acid is left from the refining process, and may be deter- 
mined by means of litmus paper inserted into the oil. If the 
litmus paper turns red after coming into contact with the oil, 
acid is present, and the oil should be rejected. 

The following are the characteristics of an oil suitable for 
use on an engine: 

(a) The oil must be viscous enough to properly support the 
bearings or to prevent leakage past the piston rings. 

(b) It should be thin enough so that it can be properly 
handled by the oil pumps, or drip freely in the oil cups. 

(c) It should not form heavy deposits of oil in the cylinder 
and cause the formation of "gum." 

(d) It should contain no free acid. 

Ordinarily a good grade of fairly heavy machine oil will be 
suitable for use on the bearings of the average engine, such as 
the cam-shaft and crank-shaft bearings. 

Only very light clean oil, or vaseline should be used on ball- 



288 GAS, OIL AND STEAM ENGINES 

bearings, as heavy greases and solid lubricants pack in the 
races and cause binding or breakages. 

Flake graphite is much used as lubricant, and too much can- 
not be said in its favor, as it furnishes a smooth, even coat over 
the shaft, fills up small scores and depressions, and makes the 
use of light oil possible under heavy bearing pressures. With 
graphite, less oil is used, as the graphite is practically perma- 
nent, and should the oil fail for a time, the graphite coat will 
provide the necessary lubrication until the feed is resumed 
without danger of a scoring or cutting. In fact, when graphite 
is used, the oil simply acts as medium by which the graphite 
is carried to the bearings. 

If graphite is injected into the cylinder in small quantities it 
greatly improves the compression, as it fills up all small cuts 
and abrasions in the cylinder walls. 

A good mixture to use for bearings is about V/i teaspoonsful 
of graphite, to a pint of light machine oil, thoroughly mixed. 

Graphite can be placed in the crank chamber of a splash feed 
engine, by means of an insect powder gun. 

Trouble with oil cups is always in evidence during cold 
weather, as the oil congeals, and does not drip properly into 
the bearings. The fluidity of the oil can be increased in cold 
weather by the addition of about ten per cent of kerosene to 
the oil. 

If too much oil is fed to the cylinders, the piston rings will 
be clogged with gum, and a loss of compression, or a tight 
piston will be the result. An excess of oil will short-circuit 
the igniter or sharp plugs, and will form a thick deposit in the 
combustion chamber that will eventually result in preignition 
or back-firing. Deposits and gum formed in the cylinder will 
cause leaky valves arid a loss of compression. Feed enough 
oil to insure perfect lubrication, but not enough to cause light 
colored smoke at the exhaust. 

Lubricating systems may be divided into three principal 
classes: Sight-feed, splash system, and the force feed system. 
Sight feeding by means of dripping oil cups is too common to 
require description, and is used on many stationary engines, 
both large and small. 

The splash system is in general use on small high speed 
engines both stationary, and of the automobile type. 

The force feed system in which oil is fed under pressure by 
a pump is by far the most desirable as the amount of oil fed 
is given in positive quantities proportional to the engine speed, 



GAS, OIL AiV ^TEAM ENGINES 289 

and with sufficient pressure to force it past any ordinary ob- 
structions that may exist in the oil pipe. 

Another system that is half splash, and half force feed, is the 
pump circulated system much used in automobiles. 

THE SPLASH FEED SYSTEM is the simplest of all, as 
the bearings are lubricated by the oil spray caused by the con- 
necting rod end splashing through an oil puddle located in 
the bottom of the closed crank case. The piston and cylinder 
are lubricated by the spray, as well as the bearings, as the 
lower end of the piston projects into the crank chamber at the 
moment that the connecting rod end strikes the oil puddle. 

To maintain constant lubrication, it is necessary that the oil 
in the puddle be kept at a constant height, or as in some cases 
be varied in such a way that the surface of the puddle is raised 
and lowered in proportion to the load on the engine. In the 
average engine the oil level is maintained by overflow pipes 
or openings that allow any excess of oil over the fixed level 
to flow back to the pump. In the Knight engine the puddles 
are formed in movable cups which are connected with the 
throttle in such a way that the opening of the throttle raises 
the oil level and supplies more oil to the engine at the greater 
load, or speed. 

Oil in splash systems is supplied by a low pressure pump, 
usually of the rotary type, in the base of the engine. Oil from 
the pump passes to the bearings, drops into the puddle, over- 
flows through the overflow opening, and returns to the pump 
through a filter, the same oil being used over and over again 
until exhausted. This strainer should be removed occasionally 
and the dirt removed, for should it be allowed to collect it is 
likely to obstruct the oil supply. The oil should be replaced 
before it becomes too black or foul, the crank case and bear- 
ings thoroughly cleaned with kerosene, and new oil replaced. 
The supply may be interrupted by the failure of the pump, 
caused by sheared keys or leakage of air in the suction line due 
to cracks. It would be well to run the engine for a few min- 
utes with the kerosene in the crank case, in order that all of 
the oil may be removed. See that the drain cock is closed at 
the bottom of the cylinder or all of the oil will be lost. Lock 
the valve handle carefully so that it cannot jar open. If light 
colored smoke appears in intermittent puffs with a multiple 
cylinder engine, it indicates that one cylinder is receiving too 
much oil. 



290 GAS, OIL AND STEAM ENGINES 

(117) Force Feed Lubricating System. 

The force feed system is by far the most reliable of all oil- 
ing systems, as it feeds uniformly and continuously at almost 
any temperature, and against the pressure of practically any ob- 
struction in the pipe. 

The oil is supplied by a small pump driven from the engine, 
the pump being incased in the oil tank housing. Frequently 
a hand pump is used in combination with the power pump when 
starting the engine, or at times when the power pump is out 
of service. A single pump is used with any number of leads, 
each lead, or feed, having an independent regulating valve and 
sight feed, or a pump unit may be provided for each lead, 
depending on the size of the engine. 

(118) Bosch Force Feed Oiler. 

The force feed of the Bosch Oiler is so positive in character, 
that the flow of oil is not affected by heavy back-pressure due 
to elbows and the diameter of the conducting pipes. Springs, 
valves and other devices, which would check the flow of oil, 
are fundamentally eliminated. The amount of oil fed may be 
accurately and permanently regulated. Glands and other pack- 
ings and bushings are eliminated. Connecting rods and all 
links are eliminated by the direct application of the movements 
of the oscillating cam disks to the pump plungers and piston 
valves. 

Each feed of this oiler is provided with a separate pump ele- 
ment consisting of a pump body plunger and a piston valve, 
the suction and feed ducts connecting directly with the pump 
body of their respective elements. With this construction, 
pump elements may be replaced or added. The oiler requires 
no attention other than to be supplied with oil; and the open- 
ing and closing of the valves, pet cocks, etc., on starting and 
stopping the machine is rendered unnecessary. The correct 
and regular operation of the elements may be verified by ob- 
servation of the reciprocating movements of the regulating 
screws. 

Each pump plunger is provided with an adjusting screw 
through which the feed may be regulated from to 0.2 cubic 
centimeters for each stroke. 

The Bosch Oiler (Fig. 121) being positively driven by the 
machine that it supplies, the oil fed is in all cases proportional 
to the engine speed; overloads are thus automatically taken 
care of. 



GAS, OIL AND STEAM ENGINES 



291 



The circular arrangement of the elements of the Bosch 
Oiler permits the device to be driven by a single shaft, and 
the oil is forced through the feeds from a single reservoir to 
the required points of application. A pump element consists 
of a pump body 1, a pump plunger 2 and a piston valve 3, 
and is supported on the base plate 13. The elements are ar- 




20 ^"^ 13 

Top View of Bosch Force Feed Oiler, 
ranged concentrically about the drive shaft in such a manner 
that the pump plungers form a circle around the circle formed 
by the piston valves. 

The pump cam disk 20 and the valve cam disk 22 are set on 
the drive shaft at other than a right angle with its axis, and 
the rims of the disks are gripped by slots formed in the heads 




25 23 » 34 

Fig. 121. Cross-Section Bosch Oiler. 

of the pump plungers and piston valves. The relation of these 
cam disks is such that the valve cam disk is 90° in advance 
of the plunger cam disk. The valve ca/n disk is solid on the 
drive shaft, but the pump cam shaft is Voose and driven through 
a lug on the valve cam disk. When the drive of the pump is 



292 GAS, OIL AND STEAM ENGINES 

reversed, the lug on the valve cam disk frees itself and again 
takes up the drive of the pump cam disk, after the drive shaft 
has made a half revolution. 

Regulating screws 4 are set in the slotted heads of the pump 
plunger, and by means of this the back-lash or play of the 
cam disk may be regulated. The regulating screws are pro- 
vided with lock nuts, and project through the cover of the oil 
tank housing, being exposed by the removal of the filler cover 
42. The filler opening is provided with a removable strainer 
to prevent the entrance of foreign particles into the oil tank. 

Pump shaft 14 is driven through worm gear 23 which meshes 
witli worm 24 on drive shaft 25; drive shaft 25 projects from the 
oiler housing, and is coupled with the driving shaft of the 
machine to be lubricated. 

Base plate 13 is attached to the oiler cover by three stud 
bolts, thus permitting the removal of the entire oiler mechanism 
from the housing. 

The quanitity of oil in the oil tank is shown by gauge glass 44. 

On the starting of the machine to which the oiler is attached, 
the pump shaft and the cam disks that it supports are set in 
motion through worm 24 and worm gear 23. A direct recipro- 
cating motion is given to the pump plunger and to the piston 
valve by the rotation of the cam disks which have a move- 
ment similar to that of the "wobble saw." The relation of the 
cam disk is such that the piston valve movements are 90° in 
advance of the movements of the pump plungers. The pump 
will run in either direction without alteration. 

To secure this effect a play of 90° is provided between the 
cam disk. When cam 22 is driven clockwise, cam disk 20 is 
driven by the lug which meshes with a lug on disk 22. The 
cams are then in such a relation that the cam valve disk is 90° 
in advance of the pump cam disk. When reversed, cam 20 re- 
mains at rest until cam 22 catches the lug and cam 20, when 
the drive continues as before. The cams are then in the same 
relation as previously for as the valve disk 22 has traveled 
through 180° it is evident that it is 90° in advance of the pump 
disk. 

(119) Castor Oil for Aero Engines. 

Castor oil is used almost exclusively in the Gnome and other 
rotary engines of the same type, but has not been particularly 
successful on stationary cylinders. 

Chemically, castor oil differs from all other vegetable or ani- 



GAS, OIL AND STEAM ENGINES 293 

mal oils in containing neither palmitine or olein. It is soluble 
in absolute alcohol, but practically insoluble in gasoline. On 
the other hand, the castor oil is capable of dissolving small 
quantities of mineral oil, the more fluid they are the less 
it absorbs of them. But the insolubility of castor oil in min- 
eral oil disappears completely when it is mixed with even a 
very small quantity of another vegetable or animal oil, such as 
colza or lard oil. An adulteration may thus result in a serious 
reversal of the oil's best qualities; in fact, in serious seizures. 
Castor oil does not attack rubber, but it contains 1 to 2 per 
cent of acid fats; sometimes more. 

"In my opinion says a writer in 'Autocar' castor oil can 
only be used in fixed cylinders with impunity for short distances 
and then with repeated cleanings between runs, but on rotary 
engines of the Gnome type cleaning is almost unnecessary. The 
reason is that one cannot consistently use castor oil over and 
over again, for the fact is indisputable that it has a far greater 
tendency than mineral oils to absorb oxygen, and so gradually 
to increase in body and finally to gum. When once it com- 
mences to gum the carbonization becomes more rapid, because 
the thickened and pitch-like oil acts as an insulating covering 
on the top of the pistons and of the cylinder, and cannot get 
away with sufficient rapidity to avoid decomposition and bak- 
ing to a coke. Therefore if castor oil is to be used on the 
ordinary stationary cylinder type of engine, it is necessary to 
wash out the crank chamber and to replace with fresh oil at 
frequently intervals. On a rotary engine such as the Gnome this 
cleaning is unnecessary, because there is a continuous stream 
of fresh castor oil brought into the crank chamber and then 
thrown by centrifugal force past the pistons and through the 
cylinder into the exhaust. Thus the stream of oil never has 
sufficient time to oxidize fully, gum or decompose. This action 
of centrifugal force accounts for the large consumption of oil 
on the rotary engine, and also for the fact that the pistons and 
cylinders keep comparatively clean. 

"In thus criticizing the use of castor oil I do not wish it to 
be inferred that it is not an excellent lubricant. What I wish 
to suggest is that in the case of an internal combustion engine 
it must be made with discretion. A point in favor of castor oil 
is the fact that it maintains is viscosity in a remarkable man- 
ner at high temperatures, and that at those high temperatures 
it has a peculiar creeping or capillary action which enables it 
to spread uniformly over the whole of the metallic surfaces. 



294 GAS, OIL AND STEAM ENGINES 

whereas under the same conditions a similarly bodied mineral 
oil would be unevenly distributed in patches. Another point is 
that the specific heat of castor oil is considerably higher than 
that of a pure mineral oil. This is in its favor, insomuch that 
it shows castor oil to be a better heat remover than a mineral 
oil. 

"Motorists and aviators have from time to time informed me 
that they are using castor oil, but have apparently been under 
some misapprehension. I find that they have been using a 
brand of prepared oil under the impression that it is a specially 
refined castor oil, or that it is a blend of castor oil." 




Producer Gas Engine Plant at Gottingen, Germany, Consisting of 
Four 3,500 Horse-Power Units. 

A simple method for testing the purity of castor oil is at 
the disposal of all. It is known as the Finkener test. Ten 
cubic centimeters of castor oil is placed in a graduate. Five 
times as much alcohol, 90 per cent, is added and stirred in. The 
solution should remain clear and brilliant at 15 to 20 degrees 
C. An admixture of foreign oils, even if only 5 per cent, riles 
the solution at this temperature, though not above it. 

(120) Force Feed Troubles. 

The most common trouble with force feed systems is the fail- 
ure of the operator to remove the dirt collected by the strainer. 
The oil piping should be cleaned out at least once every year 
by means of a wire and gasoline, to remove any gum that 
inay have been deposited. Driving belts should be kept tight 



GAS, OIL AND STEAM ENGINES 295 

to prevent slipping, and belts that are soaked with oil should 
be cleaned with gasoline and readjusted. 

Leaking pump valves generally of the ball type are a com- 
mon cause of failure. They may leak because of ,wear or by 
an accumulation of grit and dirt on their seats, which prevents 
the valves from seating properly. If the valves leak, the oil 
will be forced back into the tank, or will not be drawn into 
the pump cylinder at all, depending on whether the inlet or 
discharge valve is the offender. Plunger leakage which is rare 
will cause oil failure. 

If the oil pipes that lead to the bearings rub against any mov- 
ing part, or against a sharp edge, a hole will be worn in the 
pipe, a leak caused which will prevent the oil from reaching the 
bearing. A dented or "squashed" pipe will prevent the flow of 
oil. 

The set screw or pin holding the pulley to the pump shaft 
may loosen and cause it to run idly on the shaft without turn- 
ing the pump. This will of course, prevent the circulation of oil. 

The worm and worm wheel may wear so that the pump is 
no longer driven by the pulley shaft, or a poor pipe connection 
•may leak all that the pump delivers. 

The amount of oil required by each lead or bearing should 
be carefully determined by experiment, and kept constantly at 
the right number of drops per minute. 

The feed adjustments jar loose, and should be inspected fre- 
quently. 

(121) Oil Cup Failure. 

Oil cups should be cleaned out frequently with gasoline or 
kerosene, as any gum or lint will interfere seriously with the 
feed. They should be adjusted and filled frequently to prevent 
any possible chance of a hot bearing. 

Oil cups should be as large as possible in order that they may 
be left for considerable periods without danger of a hot box. 

Cold weather affects the oil feed to a considerable extent, 
especially with small oil cups, and they should be kept as warm 
as possible. When heavy oils are used a cold draft will stop 
the feed. 

Oils may be made more fluid in cold weather by the addition 
of about ten per cent of kerosene. 

(122) Hot Bearings. 

A hot bearing is almost a sure sign of insufficient oil, and 
the trouble should be located and remedied immediately. Oil 



296 GAS, OIL AND STEAM ENGINES 

pumps stopping, clogged oil pipes or holes, frozen oil, or oil 
leaks are common causes of hot bearings. 

Never allow an engine to run with a hot bearing for any 
length of time, as the bearing or piston may seize tight and 
wreck the engine. Inspect' the journals frequently to see if they 
are above normal temperature. A hot, binding bearing often 
causes the effect of an overload on the engine, slowing it down, 
and increasing the governor and fuel feed, this is followed in a 
"short time by the bearing seizing. 

(123) Cold Weather Lubrication. 

It is by no means uncommon trouble in cold weather to find 
excessive fluctuations in pressure as the engine speed and tem- 
perature of the oil varies. Thus, if the pressure be set correctly 
with the engine running fast, and when just started up, it will 
be found, after half-an-hour's running, that, with the engine turn- 
ing slowly, the pressure is far too low, owing to the oil having 
become thin. If the pressure be then reset, it may be found 
on next starting up from cold that the gauge goes hard over, 
and may very easily be burst if the engine is run fast. 

The point is one to which many designers of engines pay far 
too little attention, though the difficulty may be very easily 
gotten over. The secret lies in having the by-pass outlet of 
most ample proportions, so that the excess of oil, however 
thick, can get away quite easily. If there is any throttling of 
the by-pass, back pressure must result with consequent increase 
of the pressure at which the by-pass valve comes into opera- 
tion. In other words, the pressure of the main supply to the 
bearings will be increased. 

A writer to "The Motor," London solved this problem in the 
following manner: 

"Originally, the by-passage was somewhat small, little larger 
than the oil delivery pipe to the engine, which was about 3/16 
inch bore, and the result was that the pressure when starting 
with the oil cold rose to about 25 pounds per square inch, and 
fell to about one pound per square inch with the oil hot and 
the engine running slow. It was possible, however, to bore 
out the by-pass passage and fit a larger pipe, about three times 
the area of the main delivery pipe, with the result that 
the oil, when cold, never rose above about 15 pounds per 
square inch, however fast the engine run. When thor- 
oughly heated, the normal running pressure was about 6 pounds 
per square inch, falling to 2 pounds per square inch with 



GAS, OIL AND STEAM ENGINES 297 

the engine only just turning over, which brings up the ques- 
tion of the correct working pressure. This will vary very 
largely with the design of the engine, but, broadly speak- 
ing, the higher the pressure the better for the bearings. The 
limiting figure is determined by the tendency of the engine to 
throw out oil at the end of crankshaft bearings, and by the 
amount that gets past the piston rings. Obviously, an engine 
with new, tight bearings and new piston rings will stand a 
higher pressure without undue waste of oil or excess deposit 
in the cylinder head than will an old engine with worn bearings 
and slack rings. And, again, the question will be affected by 





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the design of the pistons. For instance, where the trunk of 
the piston is bored for lightness, much more oil will get past 
the rings than in cases where a 'solid' trunk is employed. 
Roughly speaking, 8 to 15 pounds per square inch is a good 
figure for a new, high-speed engine. An old and worn engine, 
particularly if not of a high-speed type, may require no more 
than 2 to 6 pounds per square inch. ,, 

"The writer recently encountered a rather curious difficulty in 
connection with obtaining a free by-pass. The return pipe 
from the by-pass led into the case carrying the gearwheels of 
the camshaft and magneto drive, and oil continually flooded out 



298 GAS, OIL AND STEAM ENGINES 

from the end of the camshaft and other bearings. The waste 
and mess were sufficiently serious to warrant investigation, and 
the cover plate over the gears was accordingly taken off. It 
was then noticed that the oil delivered to the gearwheel case 
had only two small holes by which to drain away to the crank- 
case. The flow from the by-pass was beyond the proper ca- 
pacity of these holes, and so the whole gearwheel case became 
filled with oil under considerable pressure, quite possibly 2 or 3 
pounds per square inch, and it was not surprising that oil exuded 
from the ends of the bearing. A few extra limber-holes, if one 
may borrow a nautical expression, were drilled through to 
the crankcase, and no further trouble was experienced." 

(124) Plug Oil Holes When Painting. 

When the chassis of the car is repainted it is well to see 
that all exposed oil holes are stuffed with waste to prevent 
them from being choked. Failure to observe this precaution 
may result in the holes being clogged with paint, which if not 
removed before the car is started, will prevent oil reaching the 
bearings. 

(125) Oiling the Magneto. 

Never oil the circuit breaker or circuit breaker mechanism, 
unless for a drop of sperm oil that may be applied to the cam 
roller by means of a toothpick. If oil gets on the circuit breaker 
contact points, it will cause them to spark badly, resulting in 
pitting or destruction of the points. If the oil is occasionally 
applied to the cam roller or should oil accumulate on breaker 
points, the breaker should be rinsed out with gasoline to re- 
move the surplus. 

Pitted or carbonized contact points are capable of causing 
much trouble, and gummy oil or dirt will develop this trouble 
quicker than any other cause. Use only the best grade of thin 
sperm oil on the ball bearings. 

In the course of time the circuit breaker contact points will 
wear or burn, causing imperfect contact, and too great a separa- 
tion between the points. The contacts should be examined 
from time to time, and if rough or pitted, should be dressed 
down to a flat even bearing by means of a dead smooth file, 
and the distance readjusted. The contacts should not bear on 
a corner or edge, but should bear evenly over their entire sur- 
face to insure a maximum primary current and spark. 



CHAPTER XI 
COOLING SYSTEMS 

The object of the cooling system is not to keep the cylinder 
cold, but to prevent the heat of the successive explosions from 
heating the cylinder walls to a degree that would vaporize the 
lubricating oil and prevent satisfactory lubrication of the cyl- 
inder and piston. The hotter the cylinder can be kept without 
interfering with the lubricating oil, the higher will be the effi- 
ciency of the engine and the greater the output of power. 

To obtain the greatest power from an engine, the heat devel- 
oped by the combustion should be confined to the gas in order 
that the pressure and expansion.be at a maximum, it is evident 
that the pressure and power will be reduced by over-cooling 
as the heat of the expanding gas will be taken from the cyl 
inder and transferred to the cooling rftedium. The temperature 
of the cylinder, and therefore the efficiency of the engine is 
determined principally by the vaporizing point of the lubricat- 
ing oil, and consequently the higher the grade of the oil, the 
higher the allowable temperature of the cylinder. 

If cold water from a hydrant or well be forced around the 
water jacket rapidly, the power will be greatly reduced owing 
to the chilling effect on the expanding gas. There is not much 
danger in keeping the cylinder of an air cooled engine too cool, 
in fact the great difficulty with this type of engine is to keep it 
cool enough to prevent an excessive loss of lubricating oil. 

The valves, particularly the exhaust valves, should be sur- 
rounded with sufficient water to keep them cool as they are 
subjected to more heat than any other part of. the engine, and 
are liable to wrap or pit. The water leaving the jacket q{ a 
gasoline engine should not exceed 160° F., as temperatures in 
excess of this amount cause deposits of lime scale. 

When possible, a portion of the cooling water should be run 
into the exhaust pipe immediately after it has completed its 
flow around the valves and cylinders, as the water cools the 
gas so suddenly that the exhaust to atmosphere is rendered 
almost noiseless, and the exhaust pipe is kept much cooler and 

299 



300 GAS, OIL AND STEAM ENGINES 

less liable to cause fire by coming into contact with combustible 
objects. 

On some engines the exhaust pipe is water jacketed for 
some distance to prevent dirty rusty pipes in the vicinity of the 
engine mechanism and also to prevent injury to the operator 
should he come into contact with the pipe. 

Small engines and medium size vertical engines usually have 
the water jacket cast in one piece with the cylinder casting 
and others have a separate head that is bolted to the cylinder. 

In the latter type the water flows from the cylinder to the 
head through ports or slots cut in the end of the cylinder water 
jacket that register with similar slots in the jacket of the head. 

Thus in this construction we have not only to pack the joint 
to prevent leakage of gas from the Cylinder, but also to prevent 
the leakage of cooling water from the jacket into the cylinder, 
or outside. Thus there is always a chance of water leaking 
into the cylinder bore and causing trouble unless the packing is 
very carefully installed and looked after. 

In large horizontal engines the gas and water joints are never 
made at the same point, as it would be practically impossible 
to prevent leakage into *he cylinders of such engines. 

When the cylinder and cylinder water jackets are cast in one 
piece without a water joint at the junction of the cylinder and 
the head, the water connection between the head and the cylinder 
being made by pipes external to the castings. 

Small, portable, stationary engines are sometimes "HOPPER 
COOLED," or cooled by means of the evaporation of the 
water contained in an open water jacket that surrounds the 
cylinder. 

The hopper is merely an extension of the water jacket such 
as used on all water cooled engines, the only difference being 
that the top of the hopper is open permitting the free escape 
of water vapor or steam to the atmosphere. The water level 
should be carried within two inches from the top of the hopper. 

Water when converted into vapor or steam absorbs a great 
quantity of heat, and of course the steam carries the heat of 
evaporizaticm with it when it escapes to the atmosphere. 

As the hopper is open to the air, the temperature of the 
cylinder cannot exceed 212° F. (temperature of boiling water) 
as long as there is sufficient water left to cover the cylinder. 

The hoppers contain sufficient water for runs of several hours' 
duration, and as the water boils away or evaporates, it may be 
replenished by simply pouring more water, in the top of the 



GAS, OIL AND STEAM ENGINES 301 

hopper. Hopper cooling is used principally for small portable 
engines where the weight of a water tank or other cooling 
device would be objectionable and also where there is danger 
of freezing the pipes and connections of other systems. 

The loss of water by evaporization is from .3 to .6 of a gallon 
per horsepower hour; that is, for a 5 hp. engine the loss would 
be from 1.5 to 3 gals, for every hour that the engine was oper- 
ated under full load. 

Thr cylinder and the water jacket are cast in one integral 
piece, with no joints of any kind in either the combustion cham- 
ber or in the water jacket. 

A system of cooling by which the heat of the walls is radiated 




Fig. 124. Air Cooled "Grey Eagle" Aeronautical Motor. Note the 
Depth of Cooling Ribs. 

to the air directly without the medium of water is often used 
on small high speed engines, and is known as "AIR COOLING." 
This type of cylinder is surrounded with radiating ribs or 
spires which increases the radiating surface of the cylinder to 
the extent that the required amount of heat is lost to allow of 
economical lubrication. This system is desirable where the 
weight of radiators and water would be a drawback, where it 
would be inconvenient to obtain water, or where there would 
be trouble from freezing. An air cooled motor generally is 
provided with a fan that increases the efficiency of the radiat- 
ing surface by changing the air between the ribs. With aero- 
nautical motors such as the Gnome, and Gray Eagle, shown 
by Fig. 124, the circulation of the air due to the propeller and 



302 GAS, OIL AND STEAM ENGINES 

the rush of the aeroplane is sufficient to thoroughly cool the 
machine. 

As a rule, the air cooled motor is made more efficient in fuel 
consumption than the water cooled type because of the high 
temperature of the cylinder walls. In fact all engines are air 
cooled eventually, whether the heat is radiated at a high tem- 
perature by the fires, or at a lower temperature through the 
circulating water and radiator. 

When the engines are of the portable type, and likely to be 
used out of convenient reach of water, the hopper or EVAPO- 
RATOR TANK system is used, the tank system being used 
for the larger engines. In effect, the tank system is the same 
as the hopper cooler, the heat being dissipated principally by 
evaporation, although some heat is radiated from the surface 
of the tank itself. The difference between the two systems is 
merely one of size, the tank offering a greater area for the 
-emission of heat than the hopper. 

A tank-cooled engine has one pipe running from the top of 
the cylinder to a point near the top of the tank, the bottoms of 
the cylinder and tank being connected together by another pipe. 

When the water becomes heated in the cylinder, it expands 
and becomes lighter than the cold water in the tank and con- 
sequently rises to the surface of the water in the tank through 
the upper pipe. As the warm water flows into the tank, it is 
immediately replaced by the heavier cold water that flows into 
the cylinder from the bottom of the tank through the lower 
pipe. This successive discharge of the heated water from the 
cylinder to the tank sets up a continuous flow of water through 
the water jacket of the cylinder, which transfers the excess 
heat of the cylinder to the tank where it is dissipated to the 
atmosphere by evaporation and radiation. 

The circulation of the cooling water set up by the action of 
heat or the expansion of the water is called Natural or Thermo 
Syphon circulation. 

Cooling tanks may be used profitably with stationary en- 
gines if the tank can be located so that vapor and steam pro- 
duced will not be objectionable. If the tank is used inside of 
a building, the vapor should be conveyed to the outside air by 
means of a stack or chimney, or by means of a small ventilating 
fan driven by the engine. 

The water consumption of a cooling tank is from .3 to .6 
gallons per hour, the exact quantity varying with the atmos- 
pheric conditions and temperature. 



GAS, OIL AND STEAM ENGINES 



303 



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304 GAS, OIL AND STEAM ENGINES 

If water is used from the city mains from 10 to 15 gallons 
will be required per horsepower hour, the exact quantity varies 
with the temperature of the supply. 

The water from very large stationary engines is cooled by 
allowing it to trickle down through a cooling tower, which is 
built somewhat like the screen cooler only on a larger scale. 
built somewhat like the screen cooler only on a larger scale. 
The object of the cooling tower is to present the greatest pos- 
sible surface of water to the air, this is accomplished by screens 
or baffles that turn the water over and over as it falls. The 
water, well cooled, finally collects in a cistern at the base of 
the tower from which it is pumped back to the engine and thus 
is used over and over again. This is an ideal system when 
water is expensive and when engines of considerable power are 
used. 

(126) Cooling System Troubles. 

Overheating caused by deposits of scale or lime in the jacket 
is one of the most common causes of an excessively hot cyl- 
inder. When hard water containing much lime is heated, the 
lime is deposited as a solid on the walls of the vessel forming 
a hard, dense, non-conducting sheet. When scale is deposited 
on the outside of the cylinder walls it prevents the transfer of 
the heat from the cylinder to the cooling water and consequently 
is the cause of the cylinder overheating. Besides acting as an 
insulator or heat, the- deposit also causes trouble by obstructing 
the pipes and water passages, diminishing the water supply and 
aggravating the trouble. 

Scale interferes with the action of the thermo syphon system 
more than with a pump, as the pressure tending to circulate the 
water is much lower. Whatever system is used, the scale should 
be removed as often as possible, the number of removals de- 
pending, of course, on the "hardness" of the water. 

Large horizontal engines are usually provided with hand holes 
in the jacket, through which access may be had to the interior 
surfaces on which the scale collects. Under these conditions the 
scale may be removed by means of a hammer and chisel. 

The scale may be softened by emptying half the water from 
the jacket and pouring in a quantity of kerosene oil, the inlet 
and outlet pipes being stopped to prevent the escape of the oil. 
The engine should now be started and run for a few minutes 



GAS, OIL AND STEAM ENGINES 305 

with the mixture of kerosene and water in the jacket; no fresh 
water being admitted during this time. After the mixture has 
become boiling hot, stop the engine and allow it to cool; it 
will be found that the scale has softened to the consistency of 
mud, and may easily be washed out of the jacket. 

The work of removing the scale can be reduced to a minimum 
by tilling the jacket with a solution of 1 part of Sulphuric Acid 
and 10 parts of water, allowing it to stand over night. The scale 
will be precipitated to the bottom of the jacket in the form of 
a fine powder and may be easily washed out in the morning. 

If the jacket water is kept at a temperature above 185° F. 
the amount of scale deposited will be nearly doubled over that 
deposited at 160° F. 

Wash out sand and dirt occasionally, a strainer located in the 
pump line will help to keep the jacket clear and free from for- 
eign matter. 

If a solution of carbonate of soda, or lye, and water are al- 
lowed to stand in the cylinder over night, the deposit will be 
softened and the work with the chisel will be made much easier. 

If a radiator is used (automobile or aero engine) the deposit 
can be removed with soda, never use acid, lye, or kerosene in 
a radiator or with an engine with a sheet metal water jacket. 

Obstructions in Water Pipes. Poor water circulation may be 
caused by sand, particles of scale, etc., clogging the water pipes, 
or by the deterioration of the inner walls of the rubber hose 
connections. Sometimes a layer of the rubber, or fabric of the 
hose may loosen from the rest and the ragged end may obstruct 
the passage. 

A sharp bend in a rubber hose may result in a "kink" and en- 
tirely close the opening. 

The packing in a joint may swell, or a washer may not have 
the opening cut large enough, either case will result in a poor 
circulation. 

Sediment is particularly liable to collect or form in a pocket, 
pipe elbow, or in the jacket opposite the pipe opening. Oil 
should be kept off of rubber hose connections as it will cause 
them to deteriorate rapidly, this may finally result in water 
circulation troubles. Rubber pipe joints between the engine and 
the radiator or tanks are advisable as they do not transmit the 
vibration of the engine, and hence reduce the strain on the 
piping. A strainer should be provided in order to reduce the 
amount of foreign material in the water. 

Radiators. A clogged radiator will give the same results 



306 



GAS, OIL AND STEAM ENGINES 



as a clogged jacket with the exception that steam will issue from 
the radiator if the circulation is not perfect. 

If the radiator becomes warm over its entire surface it is 
evident that the water is circulating, the temperature being a 
rough index of the freedom of the water, or the interior con- 
dition of the surfaces. A leaking radiator may be temporarily 
repaired with a piece of chewing gum. 

Should the radiator be hot and steaming at the top and remain 
cold at the bottom for a time, it shows that the water is not 
circulating and that the jackets on the cylinders are full of 
steam. Such a condition usually is indicative of clogging be- 





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tween the bottom of the radiator and pump, between the pump 
and bottom of cylinders, or of a defective pump. 

Thermo-syphon radiators are more susceptible to the effects 
of sediment and clogging than those circulated by pumps. 

A radiator may fail to cool an engine because of a slipping 
or broken belt driving the fan, or on account of a loose pulley 
or defective belt tension adjuster. Keep the belt tight. The 
fan may stick on account of defective bearings. 

Radiator may be AIR BOUND, due to pockets or bends in 
the piping holding the air. 

Rotary Pump Defects. A defective circulating pump will 
cause overheating, as it will supply little if any water to the 
jackets. 



GAS, OIL AND STEAM ENGINES 307 

Examine the clutch or coupling that drives the pump and see 
that the key or pin that fastens it to the shaft is in place. 
Next see that the driving pinion and gear are in mesh and 
properly keyed to their respective shafts. 

In some cases the shaft has been twisted off, or the coupling 
pin sheared through by reason of the shaft rusting to the pump 
casing. Worn gears or impellers IN THE PUMP reduce the 
output and cause heating, as will a sheared driving pin in the 
impeller. Wear and bad impeller fits reduce the capacity of 
the pump. 

Scale or sediment collecting in the pump sometimes strips 
the pins or impeller teeth. Note the condition of the gaskets 
or whether the pump shaft is receiving the proper amount of 
grease. Put a strainer in pump intake. See that no leak occurs 
on pump intake pipe. 

To avoid the trouble and expense due to cracked water 
jackets, never neglect to drain the cylinders and piping from 
all water in freezing weather. Drain cocks should be provided 
at the lowest points in the water circulating system for this 
purpose. It would be well to provide an air cock at the highest 
point in the line in order that all of the water can drain out 
as soon as the drain cock is opened. 

With automobile or portable engines it is not always con- 
venient or possible to drain the engine every time that it is 
stopped and consequently we must resort to a "non-freezing" 
mixture or at least a solution that will not solidify under ordi- 
nary winter temperatures. Such a solution should be chosen 
with care, as many will cause the corrosion and destruction of 
the jackets and piping; NEVER USE COMMON SALT and 
water under any conditions. 

Wood alcohol and water in equal parts, is often used for 
automobiles, but is rather expensive for portable engines hav- 
ing a comparatively great amount of water in circulation. 

Unless the circulating system is absolutely air tight, as it is 
when radiators are used, alcohol will be lost by evaporation 
and must be replaced frequently. 

The most practical solution for the average engine used, 
is made up by dissolving about five pounds of CALCIUM 
CHLORIDE in one gallon of water. This mixture will stand 
a temperature of about 15° F below zero, and if diluted to half 
the strength will not freeze above zero. 

Use CALCIUM CHLORIDE, not ordinary Salt (Sodium 
Chloride). 



CHAPTER XII 
GOVERNORS AND VALVE GEAR 
(127J Hit and Miss Governing. 

When the speed of an engine is held constant for varying 
loads by missing explosions on the light loads and increasing 
the number for heavy loads, the governing system is said to be 
of the "hit and miss type." The mixture remains constant in 
quantity and quality in this type of engine. A hit and miss 
governor allows only enough charges to be fired to keep the 
speed constant. 

When the load falls off, with a natural tendency on the part 
of the engine to increase its speed, the governor cuts out the 
next explosion by holding the exhaust valve open and the inlet 
closed, thus preventing fresh mixture from being drawn into 
the cylinder. With an increase in load, the governor allows 
the valves to follow their regular cycle with the result that a 
greater or less number are fired in succession. Hit and miss 
governing is very economical for only full charges of the most 
perfect mixture are fired, and with short exhaust pipes the 
scavenging is much better than with other forms of governing. 
The principal difficulty with this system is that the regulation 
is not as perfect as with some other types. 

(128) The Throttling System. 

Unlike the hit and miss system of governing, the throttling 
type of governor allows the engine to take an explosion on 
every working stroke, the speed being held constant by either 
regulating the quality or quantity of the mixture, or both. 
Throttle governor permits of close speed regulation as the im- 
pulses are more frequent and not so violent as with the hit and 
miss system. 

The governor acts directly on the throttle valve, and at no 
time is the operating mechanism disengaged from the driving 
cam. The throttle governor engine is particularly well adapted 
for driving dynamos, supply electric light, as the uniform speed 

308 



GAS, OIL AND STEAM ENGINES 309 

gives a smooth, steady light without the objectionable flickering 
so likely with the hit and miss engine. To obtain the best fuel 
economy with a throttling engine, it should be run close to its 
rated capacity, as the poor and imperfect mixture admitted at 
light loads considerably increases the fuel consumption. 

Practically all motors of the variable speed type such as are 
used on automobiles and motor boats are controlled manually 
by the throttle; although marine motors are often fitted with 




Fig. T6-d. De La Vergne Governor. 

governors to prevent racing when the screw is lifted out of 
the water in a heavy sea. 

(129) The Controlling Governor. 

The governor proper depends upon centrifugal force for its 
action, and generally consists of two weights which are pivoted 
at one end to a rotating shaft driven by the engine. When 
these weights are rotated rapidly the bottoms are thrown out- 
wardly by the centrifugal force and tend to assume a horizontal 
position. The faster the weights are rotated, the greater will 
be the tendency for the bottoms of the weights to come into 
the horizontal, and the greater will be the pressure exerted by 
them on the controlling levers connected to the throttle. It is 
evident that the centrifugal pull on the weights varies directly 



310 GAS, OIL AND STEAM ENGINES 




Fig. 124-d. Governor and Governor Mechanism of Fairbanks-Morse 
Type "R E" Engine. . The Fly-Balls, Springs, and Control Rods Are 
Shown on the Governor Staff. The Upper End of the Bell Crank 
Goes to the Throttle. 

with the speed of rotation and consequently with the speed of 
the engine. The exact relation between the travel of the weights 
and the speed of the engine is controlled by a spring that acts 
between arms cast on the weights and the spindle. If a heavy 
spring is used, greater speed must be attained to move the 
weights a given distance than with a weak spring, as the centri- 
fugal force must be greater. 



GAS, OIL AND STEAM ENGINES 311 

The throttle valve of the engine is connected by a rod to the 
governor through a sliding collar in such a way that the move- 
ment of the governor weights due to an INCREASE of speed 
partially closes the valve until the speed of the engine is re- 
duced. Should the speed of the engines DECREASE, owing to 
a heavy load coming on, the spring will force the balls to occupy 
a lower position which will increase the valve opening until the 
engine again reaches the normal speed for which the tension 
of the spring is adjusted. 

Thus the speed of the engine is kept practically constant by 
the action of the governor in opening and closing the throttle, 
which in turn, varies the QUANTITY of mixture admitted to 
the cylinder. The QUALITY of the mixture is varied by hand, 
in the engine by means of cocks in both the air and gas pipes. 
The GOVERNOR PROPER is of practically the same con- 
struction in the hit and miss engine, the difference of the two 
types lying in the method of connecting it to the controlling 
system. In one case (hit and miss) the governor controls the 
exhaust valve, and in the other (throttling) it controls the quan- 
tity of gas admitted by the throttle valve. The speed of the 
engine may be varied within certain limits by a lever connected 
to the valve controlling rod. 

(130) Types of Governors. 

The types of governors used on the leading makes of en- 
gines will be found described and illustrated in Chapter V which 
treats of each engine in detail. 

(131) Governor Troubles. 

Hit and miss governor troubles may be due to the following 
defects: 

.BINDING GOVERNOR COLLAR, stuck with dirt or gummy 
oil, will cause the engine to die under load, and overspeed on 
light load. m 

INLET VALVE LOCK may be worn in such a manner as 
to prevent the valve from seating during the idle strokes and 
lose fuel, or cause overspeeding. 

DETENT LEVER KNIFE EDGE may be worn, or rounded 
off, so that the exhaust valve is not held open for the idle 
stroke. This defect will cause overspeeding. 

SPEED CHANGING LEVER may work loose and cause the 
speed to vary erratically. 

GOVERNOR WEIGHTS may be stuck on pins with dirt 
or gummy oil causing engine to overspeed. 



312 GAS, OIL AND STEAM ENGINES 

LOST MOTION IN GOVERNOR GEAR such as loose pins 
and bushings, worn rollers, or bearing surfaces will cause the 
speed to vary continuously. LOST MOTION on portable en- 
gines will cause the engine to run normally in one position, 
and overspeed in another. 

WEAK OR BROKEN SPRINGS ON GOVERNOR will 
cause engine to lose speed or die down altogether. Springs 
may be stiffened by pulling out the coils. 

DRY GOVERNOR BEARINGS or joints will cause binding 
and cause governor to act sluggishly. Use plenty of lubricant. 

WORN ROLLERS may cause a speed variation. Keep the 
governor well oiled, clean, and free from gum. 

If the knife edges are allowed to slip over one another, much 
wear is caused on the cams and if allowed to continue, sooner 
or later the engine will run away. Springs will weaken with 
age and hard usage. With belt driven governors see that the 
belt is tight and that the lacing is in good condition for a slack 
belt may allow the engine to overspeed. 

I advise that every purchaser of an agricultural motor read 
his instruction book with care, that is, locate all oil holes and 
note the action and purpose of every part. If in doubt as to 
any part of its use write the manufacturer of the motor. 

(132) Throttling Governor Troubles. 

STICKING GOVERNOR VALVE will cause the engine to 
overspeed; remove the gum and dirt. 

LOOSE PINS OR BUSHINGS, or lost motion in any part 
of the governor mechanism will cause irregular motion or run- 
ning; be sure that the bearings and joints are well oiled. 

STUCK PINS will cause the engine to overspeed on light 
loads, and fall down on the normal load, or cause racing. 

WEAK OR' BROKEN SPRINGS will cause the engine to 
lose speed or to lie down altogether even on light loads. 

STIFF GOVERNOR SPRINGS cause the engine to speed up. 

SLIDING COLLAR stuck will cause racing or a fluctuation 
in the speed. Keep the governor well oiled, clean, and free 
from gum. 

The governing valve should be removed from its care fre- 
quently and thoroughly cleaned with kerosene. Deposits of 
carbon and gummed oil at this point are dangerous because of 
the likelihood of their causing overspeeding. 

(133) Valve Gear Arrangement. 

The valve operating mechanism lay-out depends upon the cyl- 



GAS, OIL AND STEAM ENGINES 



313 



inder and valve arrangement, and consequently varies in detail 
with different engines. 

Fig. F-14-15 in Chapter V, shows the valve gear of an upright 
engine having the inlet and the exhaust valves located in 




bo 
Ed 

h 



pockets placed at one side of the cylinder. The inlet valve is 
operated by a valve, rod that is actuated by the cam. The ex- 
haust valve stem is raised and lowered, directly, through a cam 
on the same shaft. The method of driving the valves in this 



314 GAS, OIL AND STEAM ENGINES 

engine is practically standard for all vertical engines having the 
valves located in pockets. This system is used in a greater 
proportion of automobile engines. 

The opposed engine has the cylinders arranged on opposite 
side of the crank case, and makes an exceedingly well balanced 
and quiet running engine; as there is no point in the revolution 
where either the crank throws or connecting rods have an un- 
equal angularity, or differ in velocity. 

While this type of two cylinder engine is common in automo- 
bile practice, it is not often met with in stationary work, the 
cam-box and the cam being directly in the center of the crank 
case. 

The opposed type of engine is particularly well adapted for 
aeroplane service as a steady, quiet running engine is an absolute 
necessity because of the frail construction of the aeroplane 
frame. 

(134) Cam Shaft Speeds. 

The valves of the gas engine are opened and closed by means 
of cams or eccentrics, that are geared to the crankshaft, and 
which also control the timing. 

As a four stroke cycle engine performs all of the events, or 
a complete cycle in two revolutions of the crankshaft, it is 
evident that the cam must go through the routine in one revolu- 
tion or must revolve at ONE-HALF OF THE CRANKSHAFT 
SPEED. 

Therefore the cam gear ratio must be as one is to two, the 
smaller gear being placed on the crankshaft, the gears being 
known as the "half time gears." 

As a two stroke cycle engine goes through the routine of 
events in every revolution, the cam-shaft must run at crank- 
shaft speed so that the cam out-line makes one revolution in 
the same time as the crank. The cam shaft speeds- given here 
apply to all engines of the corresponding cycle no matter 
whether the valves are of the poppet, rotary or slide-sleeve 
types. 

(135) Valve Gear Troubles. 

The valve gear mechanism causes trouble principally through 
the wear of the various parts which results in a change in the 
valve timing, or in the lift of the valves. Loss of power, MIS- 
FIRING, and overheating are the result of such derangements. 

Often trouble is caused in reassembling the valve mechanism 



GAS, OIL AND STEAM ENGINES 315 

after the engine has been torn down for repairs, which trouble 
may generally be traced to incorrect gear meshing. 

The following list will give the principal defects due to the 
wear of the valve mechanism. 

(a) WORN CAM GEARS change timing because of play, or 
"back lash" in the teeth, or cause a howling or grinding noise, 
that will cause the owner to believe that the end of the engine 
is near. MISFIRING and LOSS of power are probable results 
of a change in the timing. If any of the teeth are stripped from 
the gear you may be sure that the timing is changed. Replace- 
ment with a new gear is the only cure for a worn or broken 
gear. 

(b) GEARS NOT IN PROPER MESH due to an error in 
assembling the gears, will prevent the engine from being started, 
or cause misfiring and loss of power. 

The maker of the engine generally marks the teeth that go 
together, but if no such marks appear, the owner should center 
punch or scratch them before taking down the engine. 

(c) A GEAR SLIPPING ON THE SHAFT, due to a mis- 
sing key in the gear, or to a loose set-screw will cause all of 
the troubles due to a change in the timing. Examine the key 
carefully, for dirt often collects in the key-way to such an ex- 
tent that it is liable to be mistaken for the key. Keys and pins 
have sheared in two, allowing the shaft to slip in the gear. 

(d) WORN CAM-SHAFT BEARINGS are the cause of 
trouble, as they will change both the timing and the lift of 
the valves. If much play exists in the bearing, it will prevent 
the valves from lifting at the proper time, and will also reduce 
the lift by the amount of the play, which sometimes has a con- 
siderable effect on the free passage of the gases. If the cam- 
shaft bearings are of the bushing type they should be replaced 
with new paying attention at the same time to the condition of 
the shaft. If rough or shouldered the shaft should be machined 
to a dead smooth surface. If on a large engine and of the ad- 
justable type, the shims should be removed as required or the 
wedges adjusted. 

(e) LOOSE CAMS OR ECCENTRICS will change the tim- 
ing because of lost or sheared keys. If your cams are not in- 
tegral with the shaft, look them over occasionally and be sure 
that the keys are tight. Loose cams will produce thumping and 
grinding and may often be located by the sound. See that the 
key-way is not worn when fitting keys. 

If the cams are fitted with taper pins it would be well to ream 



316 GAS, OIL AND STEAM ENGINES 

the hole before placing new pins, as there is a liability of the 
hole being worn oval. 

(f) A TWISTED OR SPRUNG CAM-SHAFT will change 
the positions of the cams relative to one another, and not only 
will change the time of all cylinders, but will change their time 
relatively causing the engine to run out of balance, or produce 
an unusual vibration. 

(g) WORN CAMS are causes of a change of timing on all 
types of engines, and are the most frequent cause of reduced 
valve lift with its consequent trouble of overheating. 

If the outline or contour of a cam is changed with wear it 
should be replaced, if keyed to the shaft, as it will be a constant 
source of trouble. If the cams and cam-shaft are in one integral 
piece, it will be necessary to replace the entire shaft. 

(h) WORN CAM ROLLERS AND ROLLER PINS will 
reduce the lift of the valves, and in the case of a broken or 
sheared pin will prevent the valve from lifting at all. Always 
replace loose pins or loose rattling roller. 

(i) PUSH ROD DEFECTS. Too much clearance between 
the push rod and valve stem will reduce the lift of the valves and 
change the timing. The clearance for small engines should be 
equal to the thickness of a visiting card, and for large engines 
is somewhat larger, say 1-16". The increase of clearance is due 
principally to wear. 

Too small a clearance should be avoided for the reason that 
the valve stems expand with the heat and will lift the valves too 
soon, or even permanently until readjusted. Broken valve springs 
will cause trouble, or lost keys that retain the valve spring 
washers. Loose adjusting screws on the push rods or stripped 
threads will delay the valve opening. 

(j) TAPPET LEVER DEFECTS are generally caused by 
wear or poor adjustment. Loose pins or bushings, too much 
clearance between the tappet and valve stem or broken valve 
springs, or loose adjusting screws will produce changes in the 
timing or valve lift. 

(k) BENT VALVE ROD. A bent valve rod will shorten 
the travel of the valves, and change the timing. 

(1) CAM LEVER OR PIN will cause timing troubles if the 
pin or bushing are loose or worn, by reducing the travel of 
the valves. 

When occasion arises for the removal of valves, the oppor- 
tunity should be taken to clean the stems and guides, which 
may be more or less gummed with ancient oil. Freedom of 



GAS, OIL AND STEAM ENGINES 317 

valve movement is of extreme importance, and for this reason 
neither the cleaning nor the lubrication of the stems and guides 
should be neglected. The occasional use of a little kerosene 
will prevent gummy accumulations, but care should be taken 
not to allow the kerosene to wash out all of the oil and thereby 
leave the surfaces dry. 

A broken valve spring, though not a common occurrence, is 
not an unknown possibility. If no spare spring is at hand, a 
plan that can be recommended is to turn the broken spring end 
for end, thus bringing the finished ends up together; this will 
prevent the spring from shortening by overlapping, and wind- 
ing itself together. 

(136) Valve Timing. 

The exact time at which the valves of a four stroke cycle 
engine open and close depends to a great extent upon the speed 
of the engine, the fuel used, the compression pressure, and the 
relation of the bore to the stroke. 

As these items vary in nearly every make of engine there 
has appeared in the technical press, a great mass of seemingly 
conflicting data. Engine speed is the principal factor in de- 
termining the timing. 

Correct valve timing plays a considerable part in the output 
and efficiency of an engine, for if the inlet valve, for example, 
opens too late, the cylinder will not receive a full charge. If 
it opens too early the hot gases in the cylinder will ignite the 
gas in the carburetor and cause back-firing. Should the ex- 
haust open too late, the retention of the hot gas in the cylinder 
is likely to cause overheating. 

The timing of the valves is usually expressed in degrees of 
the circle described by the crank-pin, or the angle formed by 
the crank with the center line of the cylinder at the time the 
valve is to open or close. 

(137) Valve Setting on Stationary Engines. 

The exhaust should open when the crank lacks 30° of com- 
pleting the outer end of the power stroke, that is, the crank 
should make an angle of 30° with the center line of the cylinder 
when the exhaust valve begins to open, and should be inclined 
AWAY from the cylinder. Some makers have the exhaust open 
a little later in the stroke, but little is to be gained with a later 
opening as the retention of the charge beyond 30° heats the 
cylinder and does very little towards developing power. The 



318 GAS, OIL AND STEAM ENGINES 

only advantage of the late opening is that the valve opens against 
a lower pressure and causes slightly less wear on the parts.. 

The exhaust valve should close 5° AFTER the crank has 
passed the INNER dead .center on the exhaust or scavenging 
stroke, although some makers close the valve exactly on the 
dead center. The 5° should be given to allow the gas all possible 
chance of escape. The piston is said to be on the inner dead 
center when it is in the cylinder as far as it will go, and on 
the outer dead center when it is on the center nearest the crank- 
shaft. 

The INTAKE valve should open about 5° AFTER the exhaust 
valve closes, or 10° after the crank passes the inner dead center. 
The inlet valve should NEVER open before the exhaust valve 
closes on a low speed engine. The above timing is for engines 
running 150-600 R.P.M. The automatic type of inlet valve, of 
course, cannot be timed, but attention should be paid to the 
strength and tension of the spring and the condition of the valve 
stem guides. 

The inlet valve should close 10°' AFTER the crank passes the 
outer dead center in order that the cylinder be filled to the full- 
est possible extent. If the valve closed exactly on the dead 
center a partial vacuum will exist and the charge retained in 
the cylinder will be comparatively small, but if the valve re- 
mains open past this point the air would have time to completely 
fill the cylinder and develop the capacity of the engine. The 
longer the inlet pipe, the longer the inlet valve opening. 

(138) High Speed Engine Valve Timing. 

The faster a motor turns, all other things being equal, the 
greater the amount of advance necessary with the valves, as the 
higher the speed the less the time required to fill or empty the 
cylinder. In a short stroke high speed motor the exhaust should 
close and the intake open as early as possible in order to admit 
the full charge. The exhaust should open early to allow of the 
full escape of the gases, as the time allowed for expulsion is ex- 
tremely short when an engine runs 1,000 R.P.M. and the back 
pressure is liable to be considerable. 

The inlet valve of high speed engines should remain open for 
a considerable period after the crank passes the outer dead 
center on the suction stroke, owing to the inertia of the gases 
which tends to fill the cylinder. Lengthening the period of 
opening of the inlet valve in multiple cylinder engines produces 



GAS, OIL AND STEAM ENGINES 319 

better carbureting conditions and reduces the variations of pres- 
sure in the manifold. 

EXHAUST VALVES. The exhaust valve should begin to 
open 40° BEFORE the crank reaches the OUTER dead center 
on the working stroke, and should close 10° AFTER the crank 
has passed the inner dead center. 

INLET VALVES. The inlet valve should open 15° AFTER 
the crank passes the inner dead center on the suction stroke, 
and should close 35° after the crank passes the outer dead center. 

The inlet valve should never open before the exhaust valve 
closes, although this is done on several types of high speed 
aeronautical engines. The makers of these engines claim that 
this practice scavenges the combustion chamber more thor- 
oughly and makes the mixture more effective owing to the in- 
ertia of the burnt gases forming a partial vacuum in the com- 
bustion chamber. The writer has never been able to get satis- 
factory results with this timing and doubts whether it can be 
accomplished successfully. 

In timing an engine great care should be taken to get the 
crank exactly on the dead center. 

(139) Timing Offset Cylinders. 

The only difference in timing engines with offset cylinders 
and timing those with the center line of the cylinder in direct 
line with the crank shaft, is in the locating of the dead center. 
With no offset, the center of the cylinder, the crank pin and 
the crank shaft are all in one direct line when the engine is on 
the dead center. 

. With offset cylinders the crank pin lies to one side of the cyl- 
inder center line when on the dead center, on either the inner, 
or the outer center. To find the center on an offset engine 
proceed as follows: 

Turn the engine over slowly until the crank-pin reaches either 
the extreme top or bottom point of the crank circle, depending on 
which center is to be determined, and then turn very slowly 
until the centers of the piston-pin, crank-pin, and crank-shaft 
are in line. With the average engine this will be found a dif- 
ficult and tedious job, and it will be well to mark the dead cen- 
ter on the flywheel or other convenient point to prevent a rep- 
etition of the job. The quickest method of accomplishing the 
feat is to remove the spark plug or relief cock to gain access 
to the piston, and insert a rod or pointer in the opening thus 
provided. 



320 GAS, OIL AND STEAM ENGINES 

Draw the piston back a short distance from the end of the 
stroke with the pointer resting on the head of the piston, and 
mark this position of the piston both on the pointer, and on 
the flywheel, using some stationary part of the engine as a 
reference point. 

Now turn the crank over the center line until the piston is 
moving in the opposite direction, and is the same distance from 
the end of the stroke as shown by the mark on the pointer. 
Mark this position on the flywheel using the same reference 
mark as before. We now have two marks on the flywheel, and 
will bisect the distance between them, using the dividing mark 
to obtain the center. 

Place the bisection mark even with the reference point used 
for obtaining the two previous marks on the flywheel, and the 
engine will be on the true dead center, as the flywheel is now 
midway between two points of equal stroke. 

(140) Auxiliary Exhaust Ports. 

To decrease the amount of hot gas and flame passing over 
the exhaust valve some makers provide their engines with 
auxiliary exhaust ports, which are similar to the exhaust ports 
used on two stroke cycle engines. 

The auxiliary exhaust consists of a series of holes drilled or 
cored through a rib on the cylinder wall, the holes being so 
situated that they are covered by the piston until it is at the 
extreme end of its outward stroke. The holes are not un- 
covered until the burning charge has been expanded and cooled 
to the greatest extent possible in the cylinder. As soon as the 
piston uncovers the ports the greater portion of the dead gas 
escapes instantly to the atmosphere, carrying with them the 
greater percentage of the heat and flame. The small amount 
of residual gas that remains is forced out through the exhaust 
valve in the usual manner, thus no flame ever reaches the 
exhaust valve. 

The use of auxiliary exhaust ports produces a cooler cylinder 
as the gas passes over the cylinder wall only once, and conse- 
quently is in contact with the walls only one-half of the time 
usual with the ordinary system. The cool cylinder lessens the 
liability of PREIGNITION and decreases the consumption of 
cooling water and lubricating oil. Auxiliary exhaust ports are 
particularly desirable on air cooled engines. 



GAS, OIL AND STEAM ENGINES 321 

(141) Valves and Compression Leaks — Misfiring. 

Owing to the intense heat in the cylinder, and the action of 
the gases on the valves the seating surfaces become ROUGH 
and PITTED which causes leakage and loss of compression. 
Exhaust valves cause the most trouble in this respect as they 
are surrounded by the hot gases during the exhaust stroke 
and are much hotter than the inlet valves. 

To determine the value of the compression, turn the engine 
over slowly by hand. 

Leaking inlet valves usually are productive of BACK FIR- 
ING or EXPLOSIONS IN THE CARBURETOR intake pas- 
sages, or in the mixing valves, as flame from the cylinder 
leaks through the valve and fires the fresh gas in the intake. 

MISFIRING OR LOUD EXPLOSIONS at the end of the 
EXHAUST PIPE are indicative of leaky exhaust valves, if the 
mixture is correct and the ignition system above suspicion. 
Misfiring caused by leaky exhaust valves is due to combustible 
mixture escaping from the cylinder to the exhaust pipe and 
being ignited by the succeeding exhaust of the engine. 

If the engine has more than one cylinder, test one cylinder 
at a time, opening the relief valves on the other cylinders. Now 
take a wrench and ROTATE the inlet valve on its seat, for it 
may be that some particles of carbon or dirt have been deposited 
on surface of the valve seat which prevents the valve from 
closing properly. Rotating the valve will usually dislodge the 
deposit. 

Try the compression again; if there is no improvement, rotate 
the exhaust valve on its seat in the same manner, and repeat 
the test for compression. ROTATING THE VALVES IN 
THIS MANNER WILL OFTEN MAKE THE REMOVAL 
OF THE VALVES UNNECESSARY. When the valves are 
closed the end of the valve stem should NOT be in contact with 
the PUSH ROD, or cam lever. Suitable CLEARANCE shouid 
be allowed between the end of the valve stem and the operat- 
ing mechanism when the valve is closed; this clearance varies 
from the thickness of a visiting card on small engines to % of 
an inch on the large. If the valve stem is continually in con- 
tact with the push rod it cannot seat properly and consequently 
will leak. Wear on the valve seats and regrinding reduces this 
clearance, wear on the ends of valve stems and push rods from 
continuous thumping increases it. Keep the clearance constant 
and equal to that when the engine was new. On many engines 



322 GAS, OIL AND STEAM ENGINES 

this clearance is adjustable to allow for wear by lock nuts on 
the ends of the valve stems or push rods. 

If the above attempts have proved unsuccessful remove the 
exhaust valve from the cylinder, if the valve is in a cage, remove 
the entire cage; this may easily be done on most types of en- 
gines. Always remove the exhaust valve first as the inlet valve 
rarely requires attention. With small engines, and engines 
having the valves mounted directly in the cylinder >head it will 
be necessary to remove the cylinder head to gain access to the 
valves. In such a case use care when opening the packed joint 
between the cylinder and head, to avoid damaging the gasket. 

The exhaust valves should be lubricated with Gas Engine Cyl- 
inder Oil, never with common machine oil on account of gum- 
ming and sticking, or with gas engine cylinder oil thickened 
with FLAKE GRAPHITE. Powdered graphite may be used 
with success without the addition of oil, but oil makes the 
application of the graphite much easier. 

A cracked valve seat, due to expansion strains or to the 
hammering of the valve, is a common cause of compression 
leakage, and is rather difficult to locate as the leakage only 
occurs under comparatively high pressure. Leakage may also 
occur between the valve cage and the cylinder casting unless 
pains are taken to thoroughly clean the cage and the bore be- 
fore 'fastening into place. 

Warped valves are caused by overheating, the head of pallet 
of the valve becoming out of square with the stem, or by twist- 
ing on the valve seat. If warped valves are suspected the high 
point of the seat may be determined by means of the following 
test and should be carefully filed down until it is close to a 
bearing after which it may be ground down as described under 
pitted valves. 

If the stems are now in good condition examine the seating 
surfaces of the valve pallets and cage or rings. 

The seats should be bright and free from pits, depressions, 
or streaky blue discolorations. If the seats are deeply grooved 
from long continued leaks it is best to discard them and replace 
with new. 

Pitted valves, and those slightly grooved or streaked should 
be reground by the use of a little emery flour and tripoli which 
operation is performed as follows: 

Lift the valve from its seat and apply lubricating oil to the 
seating surface, then sprinkle a little flour or emery on the oiled 



GAS, OIL AND STEAM ENGINES 323 

surface and drop the valve back on the seat. Do not use coarse 
emery nor too much of the abrasive, a pinch is enough and 
will grind as rapidly as a pound. Take care to drop the emery 
only where required, do not sprinkle it over the engine or 
working parts as it will cause cutting and the destruction of the 
bearings. 

Now turn the valve around in one direction for about a half 
dozen turns and then in the other direction for the same length 
of time, alternately, at the same time applying a moderate pres- 
sure on the valve. Small valves may be rotated with a large 
screw driver entered in the slot found on the valve plate, but 
the handiest method is with a carpenter's brace in which is in- 
serted a screw-driver bit. 

Never turn the valve around and around in one direction 
continuously as this movement is liable to cause grooving, alter- 
nate the direction of rotation frequently with occasional back 
and forth movements made in a semi-circle. 

Do not press heavily on the valve, use only enough pressure 
to insure contact between the two seating surfaces. 

The valve should be lifted occasionally from the seat to pre- 
vent grooving, and to redistribute the abrasive, and then dropped 
back, after which the grinding should proceed as before. Re- 
move the valve after it turns without friction, wipe it clean, 
apply fresh oil and emery and grind once more. When the 
grinding has removed all pits and ridges, and presents a smooth 
even surface, the grinding is complete. To test for accuracy 
of grinding place a little Prussian Blue on the seat, if the valve 
is ground to a perfect surface the blue will show uniformly 
spread over the seat, if the grinding is incomplete bare places 
showing high spots will be seen. It is a good plan to finish the 
grinding by using a little Tripoli with oil after the emery has 
removed the pits and high spots, as Tripoli is finer than emery 
and will smooth down scratches made by the emery. 

After the grinding has been performed to your satisfaction, 
wash the valve, valve stem, and guides thoroughly with gaso- 
line and kerosene to remove the smaller traces of emery, to 
prevent wear and cutting. 

When the valves are ground in place on the engine stuff up all 
openings or parts of the cylinder to prevent the emery from 
gaining access to the bore. After grinding is complete wipe 
off surfaces thoroughly and remove waste used for stuffing. 



CHAPTER XIII 
TRACTORS AND FARM POWER 

Because of our increased population, which results in a 
greater planted acreage, and the scarcity and increased cost of 
farm labor, farming has rapidly developed into an industrial 
science. Where formerly the farmer was content to perform 
certain parts of his work by hand, he today employs machinery 
for the same task, and is far more particular as to the work- 
ing of his soil and the cost of production per acre. By the use 
of machinery his crop is marketed at less expense, in a shorter 
time, and he has more time in which to enjoy life than ever 
before. 

The modern gasoline and oil engine has been the greatest 
factor contributing to the farmer's ease and prosperity for it 
has eliminated the terrors and drudgery of plowing, churning, 
watering stock, sawing wood, threshing, and has besides given 
him many of the conveniences of city life, such as running water 
and electric light. The benefits of power are not only con- 
ferred on the farmer but his wife as well for the small domestic 
engines have saved the back of the house wife during the 
strenuous period of harvest time. 

One of the difficulties of farming is the necessity of doing 
certain work in a limited time or else suffering a heavy loss. 
The breaking, the plowing, the harvesting, and the threshing 
each must be done at a certain time, often within a few days of 
each other in order to obtain the benefits of the best weather 
conditions. Threshing starts as soon as the grain is ready, 
and if rain interferes with the threshing, the farmer can -start 
plowing immediately if provided with a tractor and thereby gain 
the undoubted benefits of fall plowing. Plowing at harvest time 
has much to do with eliminating weed seeds for the weeds are 
turned under while green, the seeds sprout and commence their 
growth and are winter killed before they reach maturity. In 
this way the field is practically freed from weeds in the spring. 
When the weather again becomes suitable, the threshing may 

324 



GAS, OIL AND STEAM ENGINES 



325 



he resumed and when completed he can again turn to his 
plowing. 

Gas power is not to be considered merely as a substitute for 
animal power for the engine not only performs the work of 




Operator's View of the "Big Four" Tractor, Showing the Four 
Cylinder Engine in Place. 

the horses but also performs work that no horse can do, and 
does it with far less expense. In the hottest weather when 
horses are dropping in the broiling sun, the tractor moves tire- 



326 GAS, OIL AND STEAM ENGINES 

iessly through the fields. Every farmer knows the expense 
attached to keeping a horse in the idle winter period for it 
must be fed, watered, and cared for, work or no work. When 
the engine is idle it costs nothing except for the interest on 
the investment, while animals grow old and are subject to dis- 
ease whether they work or not. 

The time of plowing and harvest is short and requires quick 
work, and continuous work. Horses cannot be driven at plow 
faster than one mile per hour, and cannot be worked more than 
10 hours per day, while the tractor under suitable conditions 
can travel 2 to 3 miles per hour, and keep at it twenty-four 
hours per day. An ordinary tractor can break from 20 to 40 
acres of ordinary loam per day and will plow in cultivated land 
from 40 to 50 acres per day. 

The same factors govern the fuel consumption of a tractor 
that govern the rate of plowing, that is, the character of the 
soil and the depth of plowing. On an average, \y 2 to 2y 2 gal- 
lons of gasoline will be used in breaking an acre of sod, and 
1 to 1J/2 gallons of gasoline in plowing stubble. As kerosene 
contains about 18 per cent more heat per gallon than gasoline, 
the quantity of fuel used by an oil tractor is correspondingly 
less. When used for pulling wagons on the road at about 3 
miles per hour the fuel consumption will approximate 4 gallons 
per hour, this consumption varying of course with grades, etc. 

Thirty horse-power, at the speed given above represents a 
draw bar pull of about 9,000 pounds, which is equivalent to the 
tractive effort of from 30 to 40 horses, were it possible to con- 
centrate the pull of so many horses at a single point, at one 
time. It would of course be impossible for the horses to main- 
tain this effort for as long a time as the tractor. On a level 
road it will take about 100 pounds tractive effort for each 2,000 
pounds of weight in the form of road wagons (including the 
weight of the wagon). The number of wagons that can be 
drawn with a given draw bar pull can be easily figured. When 
pulling on a grade, the effective draw bar pull will be reduced 
in proportion to the extent of the grade. While no fixed rule 
can be given regarding the number of plows that can be handled 
by a tractor, the average machine can -pull six to eight break- 
ing plows and from eight to twelve stubble plows, depending on 
the character of the soil and the depth of plowing. When the 
conditions permit the use of a greater number of plows, than 
specified above the amount of work done will of course be 
greater. 



GAS, OIL AND STEAM ENGINES 327 

A tractor can haul four ten foot seeders and two twenty foot 
harrows and cover 7 or 8 acres per hour at a cost of from 12 
to 15 cents per acre. At harvest time the tractor will also effect 
a great saving in time and ex'pense for the average machine will 
handle five or six eight foot binders, making a cut of nearly 50 
feet wide, and this can be kept up for 24 hours at a stretch. 

A tractor of the average output can handle any separator, and 
with a 44" cylinder machine can turn out from 2,000 to 3,000 
bushels of wheat and 5,000 bushels of oats in a ten hour run. It 
will also handle any of the largest shredders. For irrigation 
work, silo filling, and wood cutting it is equally efficient. 

(142) The Gas Tractor. 

The tractor of the internal combustion type using gasoline 
or oil as a fuel is much more successful than the steam machine, 
both from the standpoints of convenience and cost of operation. 
There is absolutely no danger of fire whatever around a gas 
tractor for this reason the engine can be placed in any posi- 
tion regardless of the direction of the wind, which would be 
impracticable with a steam engine. This is a great advantage 
for if the wind is allowed to blow directly from the engine to 
the separator, it will be of great assistance to the pitchers who 
feed the separator. 

When threshing or plowing in a remote field considerable 
difficulty is always experienced in supplying the steam tractor 
w r ith the. enormous amount of water that it consumes. To sup- 
ply the water requires a team, tank wagon and drivers which 
is a considerable item in the running expense. The small 
amount of water used for cooling the gas engine is renewed 
once, or at the most, twice a day. Steam coal is bulky and 
requires the continuous service of a man and team to keep 
things moving, and this expense is greatly increased by the 
expense of the coal. 

A gas tractor can be started in a very few moments while the 
engineer of a steam rig has to start in an hour or more before 
the crew to get steam up, etc. In addition to this there is the 
usual tedious routine of "oiling up," cleaning the flues, etc. 
There is absolutely no danger of explosions with the gas engine 
which have proved so disastrous in the past with steam thresh- 
ing engines. 

With the gasoline, the operator is left free to work on the 
separator as he has no firing to do and does not have to con- 
centrate his attention on keeping the water level at the correct 



328 GAS, OIL AND STEAM ENGINES 

point in the gauge glass. The engine is automatically lubricated 
in all cases so no attention is demanded on this score for it 
will run smoothly hour after hour without the least attention. 
This feature eliminates one high priced man from the job. On 
heavy loads the problem of keeping up the steam pressure is 
often a vexatious one, especially if a poor grade of coal is used. 
With a lower priced man as operator tending both the separator 
and the gas engine the crew need only consist of two pitchers 
to feed the machine, with a man and team for each pitcher. 
This small crew is easily accommodated at the farmers house, 
and does not require the services of a separate cook and camp 
equipment. 

With a gasoline rig the expenses will be approximately as 
follows: 

Engineer, wages and expenses $ 5.00 

Two pitchers, at $3.00 6.00 

Four men and teams 20.00 

60 gallons of gasoline at 15c 9.00 

Lubricating oil 1.00 



Cost per day . . $41.00 

Taking 1,500 bushels (wheat) as a day's work, the cost of 
threshing figures out at 2^4 cents per bushel. 

According to data furnished by the M. Rumely Company, 
which is based on an actual test, the total cost of plowing, 
seeding, cutting and threshing, including ground rental and 
depreciation, amounted to $8.65 with horses and $6.55 with their 
oil tractor. These figures will of course vary in individual 
cases, but are principally of interest in showing the comparative 
cost of horse and tractor operation. 

With a gasoline or oil tractor equipped with engine plows 
one man can tend to both the plows and the engine, although 
some operators prefer to have two men, one relieving the other 
consequently plowing more acres per day and reducing the cost 
per acre. In some cases one man is placed on the plows and 
the other on the engine. By running the tractor twenty-four 
hours per day, with two shifts of men, a much better showing 
is made by the tractor when compared with horse plowing, for 
with the latter method it would be necessary to supply twice 
the number of horses. 

To show the relative merits of various grades of fuel we will 



GAS, OIL AND STEAM ENGINES 



329 



print the data kindly furnished by Fairbanks Morse for a ten 
hour day. 



ITEM 



Fuel Oil 
3c 



Kerosine 

oy 2 c 



Gasoline 
15c 



60 Gallons Fuel 

Lubricants 

Engineer 

Plowman 

Repairs 

Cost to Plow 24 Acres 
Cost per Acre 



$1.80 

.40 

3.50 

2.00 

.12 

7.82 

.32 



$3.90 

.40 

3.50 

2.00 

.12 

9.92 

.41 



$ 9.00 

.40 

3.50 

2.00 

.12 

15.02 

.63 



Plowing at the rate of 20 acres per day, and kerosene at 6 2/3 
cents per gallon, the Rumely Company obtain the cost of plow- 
ing one acre as $0.66. In the latter figure the interest and de- 
preciation are included which will increase the figures over 
those given by Fairbanks Morse. It should be understood that 
these costs are approximate and? will vary considerably in dif- 
ferent localities and under various conditions. 



Oil Injection Engines. 

Engines using low grade fuels such as kerosene, usually ex- 
perience much trouble in obtaining a proper mixture when the 
fuel is vaporized in an external carbureter even when the car- 
bureter is specially designed for the heavy oil. This leads to 
fuel waste, starting troubles and cylinder carbonization, to say 
nothing of the objections of an odorous, dirty exhaust. To 
overcome the objections of carbureting the heavy oils it has 
been common practice to inject or aspirate a small amount of 
water, the water vapor tending to prevent the fuel from crack- 
ing and to distribute the temperature more uniformly through 
the stroke. The injection of water is not a particularly desirable 
feature, since its use involves one more adjustment and possible 
source of trouble when running on variable loads. 

In the semi-Diesel engine the fuel is sprayed directly into 
the combustion chamber by mechanical means, thus making the 
fuel supply to a certain extent independent of atmospheric and 
temperature conditions. After the injection the spray is vapor- 
ized both by the hot walls of the combustion chamber and the 
heat of compression, the latter being principally instrumental 
in causing the ignition of the gas. In this case no electrical 
ignition devices are required, thus at one stroke overcoming one 
of the principal objections to a gas engine. 



330 GAS, OIL AND STEAM ENGINES 

Until recently the semi-Diesel engines were confined to units 
of rather large size, the smallest being much larger than the 
engines usually used on the farm. It is now possible, however* 
to obtain oil engines of the fuel injection type in very small 
sizes, built especially for portable or semi-portable service. Not 
only is it possible to use a cheaper grade of fuel with this type 
of engine, but the fuel consumption is also less than with the 
carbureting type. To this may be added the advantages of an 
engine free from the troubles incident to the ignition and car- 
bureting systems. 

Good results may be obtained with small injection engines on 
oils running from kerosene (48 gravity) down to 28 gravity, the 
combustion in all cases being complete and without excessive 
carbon deposits. Little trouble is caused by variable loads as 
long as the speed is kept constant. Compared with gasoline, 
the heavier fuels are much safer to store and handle, owing to 
their high flash points. 

The compression of the injection engine is much higher than 
the old carbureting kerosene engine as the compression heat 
is used in a great part to ignite the oil vapor. Usually the pres- 
sure is in excess of 150 pounds per square inch, the exact value 
being determined by the form of the combustion chamber, 
whether a hot bulb is used, etc. The high compression assists 
in increasing the economy of the engine. 

Usually the piston either draws in a complete volume of pure 
air or draws in pure air through the greater part of the induction 
stroke, the spray either starting near the end of the suction 
stroke or during the early part of the compression. When a 
hot bulb is used the oil spray strikes the bulb forming vapor, 
the increasing compression caused by the advancing piston 
furnishing the air for combustion and forces the mixture into 
contact with the hot walls. Another type has no hot bulb, the 
lighter constituents of the fuel being vaporized and ignited by 
the compression alone, their inflammation serving to kindle the 
main, heavy body of the oil. In some engines, the combustion 
of the light constituents serves to spray the heavy oil through 
the valve and into the combustion chamber. Details of several 
of the most prominent makes of oil engines are described in an 
early chapter of this book. 

As a rule, this class of oil engine does not run well when the 
speed is varied through any great range, nor when governed by 
a throttling type governor, since both of these conditions affect 
the compression. They may be either of the two or four stroke 



GAS, OIL AND STEAM ENGINES 



331 



cycle type, and when of the latter they are much more success- 
ful than a two stroke cycle engine using a carbureter. 

On small engines the fuel consumption will run about 0.7 pint 
per brake horsepower hour, this consumption decreasing on 
large engines to about 0.6 pint per brake horsepower hour or 
even less. 



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332 GAS, OIL AND STEAM ENGINES 

The accompanying diagram shows a diagram of a typical oil 
engine of the injection type, a pump P supplying the oil from 
auxiliary tank to the hot, extended combustion chamber R, this 
chamber being an extension of the cylinder C-C. Oil is kept at 
a constant level in K by an overflow pipe, the oil entering from 
the supply pump through pipe J, and-entering the pump through 
M at N. By gauge glass L, the operator can tell whether he has 
a sufficient supply of oil. 

The injection pump P is driven from the eccentric E (mounted 
on the main shaft S) through the eccentric rod G and the rod H. 
The governor weights W-W alter the amount of fuel supplied by 
changing the stroke of the pump, thus keeping the speed con- 
stant under varying loads. The governor acts by shifting E in 
relation to the shaft S, a spring T controlling the throw of the 
governor. The entire governor mechanism is contained in the 
fly-wheel F. 

To start, the combustion chamber R is heated by the torch U, 
and after thoroughly heated, the starting fuel is injected by 
means of the hand lever I. This engine is of the two cycle type 
with scavenging air furnished by crank-case compression. 

(143) Construction of Gas Tractors. 

A gas tractor may be considered as being simply a special 
application of the gasoline or oil engine in which the engine 
drives the road wheels through a train of gearing instead of 
driving its load by a belt from the pulley. Four intermediate 
mechanisms must be provided between the engine and the road 
wheels in order that the tractor may properly perform its 
work. These devices are known as the "clutch," the driving 
gears, reverse gear and the "differential" gear. It should be 
understood that these mechanisms do not change the construc- 
tion or operation of the engine in the slightest, and that the 
principles that apply to the engines described in the previous 
chapters apply also to the engine of the tractor. The follow- 
ing will briefly describe the functions of the intermediate trains 
in their proper order, starting at the engine. 

The Clutch. 

A tractor is arranged to pull its load in two different ways, 
first by the draw bar, as when pulling plows, and secondly 
by a belt from the engine pulley as in driving a threshing 
machine or circular saw. In the first case it is necessary to 
drive the road wheels through the gear train, and in the second 
case it is necessary to disconnect the road wheels while driving 



GAS, OIL AND STEAM ENGINES 



333 



the thresher or saw. As the engine cannot be started while 
under load it is also necessary to disconnect the road wheels 
to free the engine while turning it over to get the first explo- 
sion. 

The device that connects and disconnects the engine from 
the road wheels is known as the CLUTCH. This usually con- 
sists of two or more friction surfaces that form a part of 
the driving gear, which may be brought into frictional con- 
tact with the engine pulley, when it is necessary to drive the 
road wheels. When the two members of the clutch are brought 
into contact they revolve together, thus connecting the engine 
with the driving gear. 

Reverse Gears. 

As it is not practicable to reverse the direction of rotation 
of the gas engine, the rotation of the road wheels is reversed 




The Reverse Gear of the "Big Four" Tractor. 



by means of gears contained in the driving train. In some 
tractors the reverse gears are similar to those in an automobile, 
being located in the transmission. In other tractors two bevel 
pinions are provided that fit loosely on the engine shaft and 
engage with a large bevel wheel that forms part of the driving 
gear. A sliding jaw clutch that revolves on the engine shaft 
is arranged so that it can connect with either of the bevel 
pinions causing them to rotate with the engine shaft and drive 



334 GAS, OIL AND STEAM ENGINES 

the main wheel. As the two pinions are on opposite sides of 
the large bevel wheel, they run in opposite directions in regard 
to it, so that it is possible to reverse the large wheel by 
engaging the clutch with either one or the other of the bevel 
pinions. 

The Differential Gear. 

The differential gear makes it possible to apply the same 
amount of power to each of the road wheels, and also allows 
one wheel to rotate faster than the other when turning around 
a corner. If both road wheels were rigidly fastened to a single 
rotating axle it would be practically impossible to turn a corner 




Differential Gear of the "Big Four" Tractor. 

for it would be necessary for the engine to slip one or the other 
of the wheels because of their difference in speed, as the outer 
wheels turn faster than the inner. 

The Driving Gear. 

The driving gear consists of a series of spur gears arranged 
for the purpose of reducing the high speed and small "pull" of 
the motor into the low speed and heavy pull of the road wheels. 
This reduction in speed is generally brought about by a 
double system of shafts, the second shaft from the motor car- 
rying the differential gear and meshes directly with the master 
gear on the bull wheel. The first shaft is an idler. 

(144) Fairbanks-Morse Oil Tractor. 

The Fairbanks-Morse 30-60 Horse-power Oil Tractor gives an 
effective draw bar pull of 9,000 pounds and develops over 60 



GAS, OIL AND STEAM ENGINES 



335 




336 



GAS, OIL AND STEAM ENGINES 






1* ~ 



IJS-Sjg-fi 



«.2 




<3 O.S 
oO © © 

ISlglsi-Sg 



horse-power at the belt pulley which is more than sufficient to 
drive any farm machinery. It will operate equally well on kero- 
sene, distillate oils, and gasoline, any of which will develop the 
rated horse-power. ' Two forward speeds and one reverse are 
obtained by a gear transmission of the automobile type, the 
forward speeds being 1^4 and 2y 2 miles per hour and the 



GAS, OIL AND STEAM ENGINES 337 

reverse \y^ miles. Combined with the governor variation, it 
is possible to get the proper speed for any kind of work. 

The fuel is sprayed directly into the cylinder with a spray of 
water, the proportion of water to oil being nearly equal at full 
load. As explained in Chapter VII, the water spray aids in 
the combustion of the heavier oils, eliminates soot and tarry 
deposits, and makes the engine run more smoothly because of 
the reduction of the explosion pressure. The spray also reduces 
the temperature of the cylinder and minimizes the dangers of 
preignition. The engine is of the slow speed type running at a 
normal speed of 375 revolutions per minute, and the two cyl- 




Fig. 127. Fairbanks-Morse Tractor Transmission with Two Forward 
Speeds and One Reverse. 



inders have a bore and stroke of 10^ X 12 inches. The speed 
regulator supplied with the engine gives an extreme variation 
of 300 to 375 R.P.M. 

The cylinders are cast two in a block which arrangement per- 
mits of the bores being brought close together and gives an 
easy circulation of cooling water. The value of this practice 
has been proved in automobile work where a simple and rigid 
structure is absolutely necessary. 

All of the valves are in the heads of the cylinder which elim- 
inates heat radiating pockets in the combustion chamber. Both 
the inlet and exhaust valve are mechanically operated through 
substantial push rods and valve rockers, and are completely 



338 GAS, OIL AND STEAM ENGINES 

surrounded by water. Large clean out holes are provided in 
the separately cast cylinder head making it accessible for the 
removal of scale and sediment. A single cylinder head serves 
for both cylinders which contributes to easy cooling pas- 
sages and a single arrangement of exhaust and inlet piping. 
The valves are in cages bolted to the cylinder head in such a 
way that they are easily removed for inspection without dis- 
turbing the piping or connections. 

The pistons are easily removed without taking the heads out 
of the cylinder or taking down any shafting. The valve rocker 
arms are provided with easily, renewed bushings and grease 
cups. As the engine is of the four stroke cycle type with both 
cylinders on the same side of the crank-shaft, only a single 
throw crank shaft is used, which is without intermediate 
bearings. 

Dual ignition is used, the high tension magneto and the two 
unit spark coils shown in Fig. 126 being independent of one 
another so that either the magneto or battery can be used for 
starting or for continuous operation. The magneto is mounted 
directly on the engine bed and is gear driven from the crank 
shaft. The ignition advance and retard lever and ignition switch 
are mounted on the engine in an accessible position. As the 
coil is mounted on the engine the leads are short and the vibra- 
tors are directly under the supervision of the operator. 

Close speed regulation is maintained by a throttling type 
governor. The voluntary speed variation used to slow the en- 
gine down to meet certain conditions encountered in plowing 
is accomplished by a small lever located at the end of the cyl- 
inders. The cooling water is circulated through the cylinders 
by a gear driven centrifugal pump. From the cylinders the 
water enters a closed radiator of the automobile type located 
at the front of the traction where it is cooled without loss. A 
nine feed, forced type oiler is used which supplies oil to the cyl- 
inders and bearings, and also to the transmission gears. Ex- 
ternal bearings which are subjected to dust are equipped with 
grease cups. The fuel pump which takes its supply from an 
80 gallon tank is in an accessible position near the operator 
and is provided with a handle by which it is operated when 
starting the engine. 

The clutch which is located in the flywheel at the right of 
the engine is operated by a lever on the footboard. All cf the 
friction faces and levers are arranged inside of the pulley so 



GAS, OIL AND STEAM ENGINES 339 

that they are not only protected from injury but are prevented 
from tearing the belt should it slip from the pulley face. 

A powerful foot with a drum on the differential gear will hold 
the outfit on a grade independent of the engine. 

The transmission is of the shifting gear type with hardened 
steel gears. The transmission gears are enclosed in a practically 
dust proof case, this being connected with enclosed crank case 
and better providing for air displacement of the pistons. Power 
is transmitted to the truck through the clutch on the left hand 
side of the engine, which is operated by combined clutch and 
shifting lever on the footboard. This lever has an interlocking 
device, arranged so that it is impossible for the operator to shift 
the gears before the clutch is disengaged, or to engage the clutch 
until the gears are completely in mesh. It is also impossible 
to get two sets of gearing in mesh at one time and prevents 
any possibility of stripping gears by applying the load on the 
corners of the teeth. 

The drive wheels are 78" diameter, 30" face. These give a 
very large bearing on the ground which is particularly desirable 
when using the engine for cultivating or seeding on plowed 
ground. The front wheels are 48" in diameter, 14" face. The 
wheel base is long and engine is easy to guide. The drive 
wheels are covered by a metal housing which protects the oper- 
ator and the working parts of the engine from dust and mud. 

This engine gives a drawbar pull on low gear of 9,000 lbs., 
which will haul from 8 to 12-14" plows, according to the char- 
acter of the plowing. The hitch is placed about 18" above the 
ground and consists of a heavy bar extending approximately 
to the middle of the bull wheels on each side, thus providing 
for hitching the load most satisfactorily. 

(145) The Rumely "Oil Pull" Tractor. 

The Rumely oil-pull tractor is driven by a two cylinder, four 
stroke cycle oil engine, having a bore and stroke of 10 X 12 
inches giving 30 tractive horse-power and 60 horse-power at 
the pulley. The cylinders are cast single and are provided 
with independent heads. The pistons are easily removed by 
unbolting the cylinder heads and the crank end of the connect- 
ing rod, after which operation they may be pulled out upon 
the platform. The exhaust and inlet valves are in easily re- 
movable cages placed on either side of the cylinder. The 
stems of the valves are at right angles to the bore of the cylin- 



340 GAS, OIL AND STEAM ENGINES 

der and open directly into the combustion chamber without 
pockets or extensions to the chamber. 

A bell crank rocker arm acts on the valve stems which in 
turn is actuated through a push rod that extends from the 
cam-shaft in the crank chamber. The cam-shaft, rocker arms, 
valves, and half time gears are clearly shown by Fig. 128. The 
housings of the inlet valves connect directly with the special 
kerosene carburetor made by the Rumely Company. The Hig- 
gins carburetor used on these engines is very simple and ef- 




Fig. 128. Phantom View of the Rumely "Oil Pull" Engine. 

fective in vaporizing the heavier fuels and has no springs nor 
internal mechanism to get out of order. The carburetor is 
controlled directly from the governor which regulates the air, 
water and kerosene required for the combustion, and has no 
manual adjustments that need attention from the operator. A 
constant flow of kerosene and water is maintained through the 
carburetor by means of force pumps, the level in the device be- 
ing kept constant by overflow pipes through which the excess 
returns to the supply tanks. 

As in nearly all types of low compression, or carbureting oil 
engines, the Rumely engine receives an injection of water in the 
cylinder to aid the combustion and cooling, and to reduce the 



GAS, OIL AND STEAM ENGINES 341 

initial pressure of the explosion. While the initial pressure is 
reduced by the water vapor, and with it the strain on the 
engine, the mean effective pressure is increased because of 
the absorption of heat from the walls and the more perfect 
combustion. The only moving part in the carburetor is a single 
plate controlled by the governor which is produced with one or 
more air passages. The governor that operates this valve is 
driven by gears and regulates the speed by throttling the 




Fig. 12Q. Higgins Oil Carburetor. 

charge. The speed of the engine can be varied from 300 to 
400 revolutions per minute while the engine is running. 

In this engine it is a very simple matter to remove the 
crank-case cover and the cylinder heads and expose the whole 
of the working mechanism of the engine. 

After removing the cylinder heads and without changing his 
position, the operator can examine, clean, and, if necessary, 
regrind the valves. Also without changing position the oper- 
ator can control his reverse transmission gears, friction clutch 
for starting the tractor. He is also in reach of the ignition 
apparatus, governor carburetor and oiler. 

The crank case is cast in one piece. The bearings are cast 
integral with the crank case, and are fitted with interchange- 



342 



GAS, OIL AND STEAM ENGINES 



able, adjustable, babbitted shells. Binder caps hold the bear- 
ings together and keep the babbitted shells securely in position. 
The design permits removal of binder caps for examination of 
crank shaft bearings without distributing the adjustment. The 
crank case is secured to tractor frame by well fitted bolts, 
thereby avoiding annoyance from loose bolts and nuts. 

The crank case is covered with a sheet steel lid that shuts 
out all dust and dirt. This cover can easily be removed at 
any time by simply unscrewing the bolts that hold it in place. 
It is constructed with this cover on top instead of on the side 




Fig. 130. Rumely Oil Pull Tractor. 



or end, which permits of easy access to any working parts in 
the crank case. 

To further facilitate the accessibility to working parts in the 
crank case, a secondary cover is provided which can be removed 
in a couple of minutes. This opening is large enough to allow 
the operator to reach any point within the crank case. 

All cams are key-seated upon the cam shaft with double key- 
seats, which absolutely prevent any possibility of slipping or 
alteration in the timing of the engine. The exhaust and intake 
valves are mechanically operated. The valves are constructed 
with steel stem, nickel-steel heads, the whole being highly 
finished. 

Valve cages are oil cooled, thereby eliminating all possibility 



GAS, OIL AND STEAM ENGINES 343 

of the valves overheating or warping. The valves themselves 
can be removed by simply unscrewing the connection. The 
engine is provided with a set of relief cams by which the com- 
pression can be relieved — this greatly facilitates the starting of 
the engine. 

The piston is equipped with five self-expanding rings. Con- 
necting rod is of drop-forged steel construction. Crank-pin 
bearings are made in halves. and lined with shells of special 
metal. 

A combination of mechanical force feed and splash lubrication 
is employed. Six force feed tubes enter the crank case, on to 
each bearing, and two tubes force oil into the cylinder. The 
crank case contains two gallons of oil and is arranged so that 
any surplus may be drawn off immediately. The lubricator 
has a gauge glass that shows the quantity of oil supplied at 
all times, and which is always in view of the operator. 

A make and break system (low tension) furnishes the igni- 
tion spark, which is supplied with current by a Bosch low ten- 
sion magneto under normal running conditions, and a battery 
for starting and for use "when the magneto fails. The mag- 
neto is of course gear driven so that its amature has a fixed 
relation with the piston position. The igniters of either cylin- 
der may be easily removed for examination by simply unscrew- 
ing two nuts. 

Oil is used as a medium for carrying heat from the cylinder 
walls to the radiator. In the construction of the cooler the 
company have followed new principles, thus accomplishing the 
desired result with a minimum amount of metal and liquid. 
There is no surplus of liquid, just* enough oil being used to fill 
the cylinder jackets, radiator and circulation pipes. The oil 
is kept in a constant flow from the cylinders to the radiator 
and back to the. cylinders by a large pump which is driven by 
a chain direct from the crank shaft. The radiator is self-con- 
tained and will hold the oil for an indefinite period. 

The radiator is composed of a number of sections of pressed 
galvanized steel. Oil circulates freely within the sections and 
the air is drawn round the outside. There is a constant flow 
of oil inside and a constant current of air outside. 

The engine is provided with a smooth-working, efficient fric- 
tion clutch, which is easily handled by a platform lever and 
with little exertion on the part of the operator. The toggle 
bolts are adjustable so that any wear in the blocks can be 
taken up. 



344 GAS, OIL AND STEAM .ENGINES 

The clutch and brake are so connected that when the clutch 
is thrown out the brake is immediately applied and when thrown 
in the brake is released. 

The various movements of the valves and the ignition mech- 
anism on the face of the flywheel, are marked so that one can 
check up the timing of the engine. By bringing any one of 
these marks to coincide with the stationary pointer attached 
to the side of the crank case, one can easily ascertain whether 
the adjustments and the timing are exact. 

The crank shaft is supported by two end, and one intermedi- 
ate bearing, the latter bearing being placed between the two 
throws of the crank shaft. As the two cylinders are placed 
on the same side of the crank shaft, the two throws are -also on 
the same side of the shaft and to balance these throws cast iron 
counter weights are bolted on the bottom of the crank arms. 
The bearings are exceptionally long, the total length of the 
three bearings amounting to more than half the length between 
the outer ends of the bearings. 

The frame of the tractor consists of four twelve inch "I" 
beams securely riveted together with intermediate channel stiff- 
eners. The cast steel bearings are riveted to the frame so 
that the whole construction is one unyielding mass. The bear- 
ings are in halves which makes the removal of the shafts an 
easy task. 

With, the exception of the differential and master gears all 
of the gears are cut out of semi steel blanks. The fly wheel 
has a face of 11 inches, and a diameter of 36 inches. 

(146) The "Rig Four" Tractor. 

The Big Four tractor differs from the majority of tractors in 
having a four cylinder vertical type motor of 30 tractive and 
60 brake horse-power capacity. The cylinders have a bore of 
6]/ 2 inches and a stroke of 8 inches. The engine runs at the 
comparatively high speed of 450 revolutions per minute. Gaso- 
line is used for fuel, and is vaporized in a conventional type of 
jet carburetor. 

Both the inlet and the exhaust valves are placed in a pocket 
at one side of the cylinder making what is known as an "L" 
engine. The cylinders and the heads are cast in one piece, 
doing away with points between the cylinders and heads. The 
pistons and connecting rods may be removed without disturb- 
ing the cylinders or their connections by pulling them out 
through hand holes in the base of the crank case. 



GAS, OIL AND STEAM ENGINES 345 

The four throw crank shaft is provided with five bearings, 
these intermediate bearings between the throws and two end 
bearings in the case. The interior working parts of the motor 
are lubricated by the splash system with a positive forced feed 
oiler. The splash pools can be adjusted at a minute's notice 
so that any desired oil level can be obtained. Grease cups pro- 
vide the lubrication for all bearings outside of the motor. 

Water is circulated by a direct driven centrifugal pump, and 
as the cooling water is in a closed system the same water is 
used over and over again without much loss, a bucketful or so 
a day being an ample supply. The tublar radiator situated in 




Fig. 131. Views of the Four Cylinder Motor of the "Big Four" Tractor. 
Note the Massive Construction Compared with Automobile Practice. 

the front of the tractor is provided with a cooling fan that is 
driven from the engine in a manner similar to automobile prac- 
tice. A high tension magneto is gear driven from the cam 
shaft, and is mounted on a rocking bracket so that the arma- 
ture is advanced and retarded as well as the circuit breaker. 

An internal expanding clutch connects the- motor with the 
driving gear by operating on the inner run of the fly-wheel. 
The motion of the engine is transmitted to an intermediate 
reversing device through bevel gears, this being necessary for 
the reason that the crank-shaft runs "fore and aft," or parallel 



316 



GAS, OIL AND STEAM ENGINES 



to the length of the tractor. A double acting jaw clutch en- 
gages with either one or the other of a pair of bevel pinions 
that run in opposite directions. Motion from the reverse gear 
is transmitted directly to the different shaft, and from there it 




"Big Four," Four Cj'linder Tractor Motor. 

is transmitted to the master gears on the bull wheels. The 
differential shaft is in one piece. 
The main driving wheels are very large when compared with 




Showing the Position of Engine on "Big Four" Tractor. 

the wheels of an ordinary tractor, for they are eight feet in 
diameter and are proportionately broad. This no doubt gives 
splendid tractive effect in soft and uneven fields and must save 



GAS, OIL AND STEAM ENGINES 



347 



the machine from "stalling" under adverse conditions. An- 
other unusual feature is the automatic steering device used in 
plowing. This device consists of a long tublar boom that is 
fastened to the swiveled front axle of the tractor and a small 
wheel fastened to the outer end of the boom. The small 
wheel rolls in the next furrow and compells the tractor to plow 
in a line parallel to it. This steers the tractor more accurately 
than would be possible by hand and at the same time enables 
one man to operate both the engine and the plows. 




348 



GAS, OIL AND STEAM ENGINES 



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CHAPTER XIV 
THE STEAM TRACTOR 

(147) The Steam Tractor. 

The steam tractor consists of the following elements, which 
will take up in detail under separate headings. 

(1) Engine proper, consisting of the cylinder, piston, valve 
motion, guides, crank, fly wheel, etc. 

(2) Boiler — with the grates, burners, etc. 

(3) Feed pump or injector. 

(4) Feed water heater. 

(5) Driving gear, differential, clutch, etc. 

As in the case of the gas tractor, the machine consists simply 
of a steam engine and its boiler that drive the road wheels of 
the tractor through a gear train. With the steam tractor the 
gearing is simplified as the reverse is performed by the engine's 
valve motion, and not through gearing. There is no need of 
speed changing transmission gears in the steam tractor as the 
engine is sufficiently flexible to provide an innumerable number 
of speeds by simple throttle control. 

While the fuel most commonly used is coal, straw and wood, 
crude oil is often used, the fuel being determined principally 
by the location of the engine, and by its cost on the job. The 
matter of fuel should be taken into consideration when the 
engine is purchased as the different grades demand different 
fire box and boiler construction. When it is possible to obtain 
crude oil at a reasonable figure, it certainly should be used in 
preference to all others as liquid fuel is the most compact, 
most easily controlled, and efficient of any. The subject of oil 
burners is taken up later in this chapter, a number of types of 
which are clearly illustrated. 

(148) The Cylinder and Slide Valve. 

The steam engine cylinder consists essentially of a smoothly 
bored iron casting in which a plunger called the "piston" slides 
to and fro, the cylinder acting not only as a container for the 
steam acting on the piston but as a guide and support as well. 

349 



350 GAS, OIL AND STEAM ENGINES 

Needless to say, the contact or fit between the piston and cyl- 
inder walls must be as perfect as possible, tight enough to pre- 
vent steam passing the piston, and free enough to allow the 
piston to slide without unnecessary friction. The reciprocating 
piston is connected to the crank through a connecting rod by 
which the pressure on the piston is communicated to the crank 

arm. 

The pressure exerted on the crank pin by the piston depends 
on the area of the piston (in square inches) and the pressure 
of the steam on each square inch of the area. With a given 
steam pressure, the greater the area, the greater the force tend- 




ing to turn the crank. As power is the rate or distance through 
which the force acts in a unit of time it is obvious that the 
power developed by the engine is equal (in foot pounds) to the 
force in pounds multiplied by the velocity of the piston in feet 
per minute. Since there are 33,000 foot pound minutes in a 
horse-power, the power developed by such a cylinder is equal 
to the force* multiplied by the piston velocity, divided by 33,000. 
As the cylinder is necessarily limited in length it is evident 
that the piston cannot travel in one direction continuously but 
must be reversed in direction when it travels the length of the 
cylinder bore thereby traveling the next distance in the oppo- 
site direction. This reversal of the piston is accomplished by 
admitting the steam in one end of the cylinder and then into 
the other, this causing the steam to act on the opposite sides 



GAS, OIL AND STEAM ENGINES 351 

of the piston alternately. To establish a difference of pressure 
on the two piston forces, the steam pressure is relieved on one 
side while the steam acts on the other. 

A typical cylinder furnished with the ordinary steam tractor 
is shown by Fig. 133, in which T is the cylinder, P the piston 
and R is the piston rod. When the steam in the cylinder end 
E acts in the direction shown by arrow E, the piston pulls the 
rod R in the direction shown by arrow S, the pressure in the 
cylinder end D being relieved to atmospheric at this time. 
The steam is admitted and relieved by the valve L which slides 
back and forth on its seat actuated by the valve rod VR. 

In the position shown, the valve L is moving to the left as 
shown by arrow O. The edge of the valve N is just opening 
the steam port G through which the cylinder end F is placed in 
communication with the steam filled valve chest A. Steam at 
boiler pressure fills the space A, which flows into E past N 
and through G when the valve opens and establishes pressure 
against P, which, through the piston and connecting rods turns 
the crank. 

The steam is exhausted from the cylinder end D, through the 
port F, through the exhaust port U, and out of the exhaust pipe 
X. As wall be seen from the figure, the inside valve edge Y 
has moved to the left so that the port F is fully opened. When 
the piston reaches the left hand end of the cylinder, the valve 
L moves to the right so that the end of the cylinder E is con- 
nected to the exhaust port V through the cylinder port G, thus 
allowing the steam in the space E to pass out of the exhaust pipe 
X. A further movement of the valve to the right causes the 
left edge Z of the valve to uncover the cylinder port F which 
allows the steam to flow into the cylinder space D and push 
the piston to the right. This motion is carried on continuously, 
the valve moving in a fixed relation to the piston, and admits 
the steam and releases it first on one side of the piston and 
then on the other. The valve shown is known as a "D" valve 
and is one of a variety of valves furnished with steam engines, 
which, however perform exactly the same functions as the valve 
shown. 

An "eccentric" which is really a form of crank, drives the 
valve to and fro, the eccentric being fastened to the crank- 
shaft. The full pressure of the steam forces the D valve down 
on its seat, and as the valve is of considerable size, this pres- 
sure causes much friction and power loss. In some engines a 
"balanced" valve is used in which the pressure on the valve 



352 GAS, OIL AND STEAM ENGINES 

is balanced by an equal pressure that acts on the under side of 
the valve face. Balanced or unbalanced, the function of the 
slide is to alternate the flow of steam in the two ends of the 
cylinder. 

Steam is prevented from passing the piston into the oppo- 
site end of the cylinder by elastic rings placed in grooves on 
the piston which are known as "piston rings." Being thin and 
elastic these rings instantly conform with any irregularity of 
the piston bore and effectually stop the flow of steam past them. 
At the point where the reciprocating piston rod R passes 
through the cylinder, a steam tight joint is made by the "stuff- 
ing box" or gland H. The space between the inner walls of 
the stuffing box and the piston rod are either filled with some 
description of fibrous packing or a metallic packing that fits 
around the rod in the same manner that the piston rings fit in 
the bore of the cylinder. The packing is arranged around the 
valve rod VR in the same manner. 

As the piston, piston rod, and valve slide on their respec- 
tive surfaces with considerable pressure it is absolutely neces- 
sary that these parts receive ample lubrication. In practically 
all engines the oil is taken into the cylinder with the steam in 
the form of drops, the oil being measured out by a sight feed 
lubricator that is tapped into the steam supply pipe. In this 
device, the oil from the lubricator reservoir is fed through a 
regulating needle valve, drop by drop, up through a gauge 
glass so that the engineer can tell the amount of oil that he 
is feeding. The body of the lubricator is filled with condensed 
water up to the level of the outlet through which the oil passes 
into the cylinder, and the entire lubricator, reservoir and all is 
under boiler pressure at all points. The oil regulating valve 
is placed at the bottom of the lubricator, and as oil is lighter 
than water, it floats up from the valve to the level of the out- 
let, through the gauge glass, and from the outlet level floats 
out into the steam pipe and mixes with the steam. By floating 
the oil in this manner, the engineer can see every drop that 
is fed. 

(149) Expansion of Steam. 

In order to reduce the amount of steam used, the valve does 
not allow the steam to follow the piston at full boiler pres- 
sure through the entire stroke, but cuts it off at a certain 
point after the piston has started on its travel. As the vol- 
ume of the steam is increased by the further travel of the 



GAS, OIL AND "STEAM ENGINES 353 

piston after the point of cut-off, the steam expands in volume 
until the end of the stroke is reached, at which point the 
pressure is naturally much below the initial or boiler pressure. 
This reduction in temperature and pressure results in a wider 
working temperature range than would be the case with the 
steam following the piston throughout the stroke, and as the 
steam is exhausted to atmosphere at a temperature much lower 
than that of the boiler steam, much less heat is carried out 
through the exhaust. As a general rule, the most economical 
point of cut-off is at y± °f tne stroke. Engines requiring more 
steam than is supplied at l /^ cut-off in order to carry the load, 




Fig. 134. Case Steam Tractor. 



are too highly taxed for efficient results. Since the most effi- 
cient point of cut-off is only J /^ of the possible steam travel it 
is evident that an engine can carry a load much greater than 
that for which it is rated, but it is also evident that this in- 
creased capacity is gained at the expense operating economy. 
Wear and tear on the engine parts are also duly increased. 

(150) Speed Regulation. 

On steam tractors a constant speed is maintained by "throt- 
tling" the steam, to meet the demands of the load by partially 
restricting the flow of steam at light loads and opening the 



354 GAS, OIL AND STEAM ENGINES 

inlet at full load. The valve that controls the steam for the 
different loads is controlled by a "governor" which depends 
on the centrifugal force exerted by two fly-balls. The balls, or 
weights are hinged to a revolving spindle, driven by the en- 
gine, in such manner that an increase of speed tends to straighten 
out and revolve in a more nearly horizontal plane. The amount 
of travel of the balls for a given speed increase, is governed 
by a spring, which returns them to a vertical position when 
the speed decreases. By means of a simple system of levers, 
the valve is closed when the balls fly out, due to an increase 
of speed, and is opened when the speed decreases, so that the 
engine will receive the steam at a higher pressure and again 
build up its speed to normal. As the load fluctuates, the balls 
are constantly moving up and down, seeking a valve position 
that will keep the engine at a constant speed. 

Speed variation is generally accomplished by increasing or 
decreasing the tension of the spring that controls the travel 
of the governor fly balls, and in the majority of engines this 
may be done without stopping the engine. 

Another form of governor used extensively on stationary en- 
gines controls the speed by increasing or decreasing the cut- 
off. Thus with a heavy load the cut-off may occur at Yz the 
stroke while with a very light load it may be at 1/10 stroke. 
This is by far the most sensitive and economical form of gov- 
ernor, but on account of the reverse gear it is difficult to apply 
it on a tractor. 

(151) Reverse Gear. 

As explained under "Cylinders" the travel of the valve bears 
a definite relation to the piston position so that the ports may be 
opened and closed at the proper times. It may be shown by 
a rather complicated diagram that this relation of the valve 
together with that of the eccentric that drives it is only correct 
for one direction of rotation. For any other direction of rota- 
tion the relation of the valve and piston position must be 
changed. This may be done in several ways but the most 
common types are the Stevenson Link and the Wolff slotted 
yoke. 

The Stevenson link motion used on the majority of engines, 
consists of two independent eccentrics, one being fixed in 
the relation for forward motion and the other for the reverse 
direction. The ends of the eccentric rods leading from 
these eccentrics are connected by a slotted bar or link, in 



GAS, OIL AND STEAM ENGINES 355 

which a block is placed that is connected with the valve rod. 
The block is free to slide in the slot of the links, that is, it may 
be moved from one end of the slot to the other. When it is 
desired to have the engine rotate in a right handed direction, 
for example, the link is lowered so that the rod from the for- 
ward eccentric is brought directly in line with the block so 
that this eccentric alone acts directly on the valve through the 
valve stem. When the reverse is desired the link is raised 
until the rod from the reverse eccentric is brought in line with 
the block and valve stem, drive being by the reverse eccentric. 

When the block is on the link in a position between the two 
points mentioned, the valve has less travel and it cuts off 
earlier in the stroke than when driven directly by one eccen- 
tric, for the motion at an intermediate point on the link is 
much different than at the ends of the slots. This fact is taken 
advantage of in operating engines with the idea of economy 
in view, and is known commonly as "hooking up" the engine. 
The best point at which to "hook up" the engine is best deter- 
mined by experiment, and is equivalent in many respects to 
the problem of advancing and retarding the spark of a gas en- 
gine. We earnestly advise an engineer of a traction engine to 
take up this subject and determine the best point of cut-off 
for different loads as he will find that different positions make 
a considerable difference in his coal bill. Of course the proper 
way is to determine this point with a steam engine indicator, 
but as few engineers have such an appliance, the work is gen- 
erally of the cut and try order. Wear and varying adjust- 
ment soon change the points marked on the reverse sector, and 
for economy's sake these points should be checked occasion- 
ally. 

In the Wolff motion, a single eccentric is used for both 
directions of rotation, in connection with a slotted link. A 
single eccentric is securely keyed to the crank shaft. The eccen- 
tric strap has an extended arm which is pivoted to a block that 
slides back and forth in a curved guide. The angle at which 
the guide stands with the horizontal determines the direction 
of rotation, the angle being changed by the reverse lever. The 
degree of the angle made by the block also determines the point 
of cut-off. This is a very efficient and simple valve gear. 

Guides and Cross-Head. 

The outer end of the piston rod is supported by a sliding 
block known as the "cross-head" which in turn is supported 



356 GAS, OIL AND STEAM ENGINES 

by the guides. An oscillating rod called the "connecting rod" 
connects the reciprocating cross-head with the crank pin, this 
rod is used in the same way as the connecting rod of the gas 
engine except that it is connected to the cross-head instead 
of the piston. 

Clutch. 

The clutch affords a means of connecting and disconnecting 
the driving wheels and engine shaft. It is usually of the fric- 
tion type described under "Gas Tractors." By releasing the 
clutch the engine is disconnected from the driving gear so 
that the tractor remains stationary while the engine is driving 
a load through the belt. 

Use of the Exhaust Steam. 

The exhaust from the cylinders is used in two ways, first to 
create a draft for the fire, and second to heat the feed water 
pumped into the boiler. The draft is increased by exhausting 
a portion of the steam into a nozzle placed directly under the 
stack. The friction of the steam on the surrounding air, 
draws the air with it, forming a partial vacuum over the grate 
at each puff, and in this way it causes additional air to rush 
through the fuel and increases the temperature of the combus- 
tion. As the load increases the "puffs" increase in intensity 
due to the greater terminal pressure and the fire is ac- 
celerated in proportion. This is a simple but rather expensive 
way of increasing the draft. 

A considerable proportion of the heat in the exhaust steam 
i>s saved by using it to heat the feed water supplied to the 
boiler. Besides the saving in fuel, affected by heating the 
water from steam that would otherwise be thrown away, the 
strains on the boiler due to the injection of cold water are 
greatly decreased as the difference between the temperatures of 
the boiling water in the boiler and the hot feed water are 
much less than in the former case. 

The feed water heater consists essentially of a series of tubes 
in a cylindrical shell. The tubes are surrounded on the outside 
by the feed water, and are filled with the exhaust steam which 
passes from end to end through the tubes. The hot water is 
pumped from the heater into the boiler. An efficient feed water 
heater adds greatly to the steaming capacity of the boiler. 



GAS, OIL AND STEAM ENGINES 357 

(152) Feed Pump. 

A small steam pump is furnished for pumping the water into 
the boiler. This device consists of a small steam cylinder con- 
nected directly with the pump plunger and is absolutely inde- 
pendent of the main engine so that it can be used whether the 
engine is runnig or not. The exhaust of the pump should be 
turned into the feed water heater when the engine is not run- 
ning so as to heat the water, but should be directed to atmos- 
phere when the main exhaust is passing through the heater. 
An injector is usually supplied with the engine for feeding the 
boiler in emergencies. 

The injector forces water into the boiler by means of a 
steam jet which is arranged so that a high velocity is imparted 
to the water in the injector nozzle by the condensation of the 
steam furnished by the jet. In this way water is pumped into 
the boiler against a pressure that is equal to the pressure of 
the steam acting on the water. Except for a check valve there 
are no moving parts. No feed water heater connection is 
made with the injector for this device raises the temperature 
of the feed to a considerable temperature. The temperature 
is not as high, however, as the temperature of the water from 
the feed water heater and pump, and because of the compara- 
tively low temperature coupled with the fact that live steam 
is used in heating the injector water, it is not an economical 
method of pumping. 

(153) The Boiler. 

As the boilers of traction engines sustain the pull and vibra- 
tion of the engine as well as the stresses due to traveling over 
rough roads in addition to the steam pressure strains, they 
must be made very substantially and of the best materials. The 
service of the boiler on a traction engine is very different from 
that met with in stationary or locomotive practice for the 
tractor seldom receives the attention that is given to the other 
types and as it goes bumping over the fields with the water 
whacking at every joint and the engine rushing and surging 
at every little grade, it receives an "endurance" test every mo- 
ment of its existence. 

A boiler should show an inspection pressure considerably in 
excess of that which it is intended to carry. It should be well 
stayed and braced, and should be suspended from the road wheels 
in such a way as to be relieved from as much strain as pos- 
sible. No transverse seams should be permitted, and the barrel 



358 GAS, OIL AND STEAM ENGINES 

should be well reinforced at the point where the front bolster 
is attached as well as at points where pipe connections are 
tapped into the shell. No large bolts should be tapped into 
the steam or water space. The tubes should be placed so 
that they may be easily withdrawn or cleaned. The location 
of the hand holes and washout holes is also an important item, 
for inaccessible hand-holes are an abomination. 

Boiler lagging or covering is intended to reduce the heat 
loss by radiation, and for this reason it should be of a good 
insulating material and should be thick enough to be effective. 
The cost of jacketing is more than covered by the saving in 
coal, especially in cold weather. 

A straw-burning fire box differs from a coal burner in having 
a fire brick arch and a shorter grate, and in having a special 
chute on the fire door for feeding the straw into the furnace. 
After a short time, the fire brick arch becomes incandescent, 
keeping the fire-box temperature constant and producing perfect 
combustion of the tarry vapors distilled from the straw. A 
trap door is provided on the straw chute which automatically 
keeps the outside air from chilling the fire. 

(154) Oil-Burning Steam Tractors. 

As with the straw-burning furnace, a brick arch is used in 
burning oil for the purpose of preventing fractional distillation 
of the oil during the combustion. In some forms of oil furnaces 
a brick checker-work is used that provides a much greater sur- 
face to the gases than the ordinary firebrick arch and there- 
fore keeps a steadier temperature and pressure. Broken fire- 
brick in the furnace placed in heaps with a rather porous for- 
mation is also an aid to combustion. With very heavy oils a 
jet of steam in the firebox is of great assistance in consuming 
the free carbon of the fuel (soot). 

The oil in practically all cases is atomized or is broken up 
into a very finely subdivided state by the action of a jet of 
steam. The finer this subdivision the better will be the com- 
bustion for the oil particles will be brought into more intimate 
contact with the air. Provision is also made in the burner for 
either whirling or stirring the oil vapor with the air so that 
a rapidly burning mixture is formed. In other respects the oil 
burning engine is the same as the coal or wood burner. 

(155) Care of the Steam Tractor. 

During the idle season, the engine should be well housed, all 



GAS, OIL AND STEAM ENGINES 



359 



bright parts slushed with grease and the whole engine care- 
fully covered with tarpaulins. A tractor is an expensive ma- 
chine and should be given care, or it will rapidly depreciate 
and start giving trouble. When one considers the abuse and 
neglect given farm machinery it is remarkable that it will work 
at all, let alone give efficient service. 

Before starting a new engine or one that has been idle for a 
considerable time, all of the bearings and lubricating should 




Small Fairbanks-Morse Motor Driving Binder. 

be thoroughly cleaned with kerosine oil, removing all grit 
or gum. After cleaning, they should be thoroughly oiled with 
the proper grade of lubricant and then adjusted for the correct 
running fit, taking care that the bearings and wedges are not 
taken up too tight, nor too many shims are taken out. Be sure 
that the openings in the lubricating cups and oil pipes are not 
clogged and that oil holes in the bearing bushings register with 
those in the bearing caps. At points where there are sight 
feed gauge glasses, the glasses should be cleaned with gasoline 
and all of the joints repacked with new packing. 



3^0 GAS, OIL AND STEAM ENGINES 

Careful attention should be paid to the piston rod and valve 
rod packing taking care that it is only tight enough to pre- 
vent the leakage of steam and no greater. Excessively tight 
packing burns out rapidly, scores and shoulders the piston rod, 
making it impossible to keep the joint tight. When rods are 
badly scored they should be trued up in the lathe taking care 
not to take off too much metal on the finishing cut. When 
renewing fibrous packing be sure that all of the old packing 
is removed before placing the new packing in the box. Keep 
the packing well lubricated at all times to prevent wear, and 
in some cases it will be advisable to add an oil cup to the 
stuffing box to insure sufficient lubrication. 

Go over the valve gear and make sure that there is no loose- 
ness or play in the eccentrics or pins, and that all of the bolts 
and keys are tight and in place. Loose connections in the valve 
gear are not only productive of knocks and wear but also tend 
to increase the fuel consumption of the engine. When possi- 
ble, indicator cards should be taken at intervals to make sure 
that the valves are correctly set. In a test recently made by 
the author, ,the indicator cards showed a defective setting due 
to Wear, that when corrected saved the owner of the engine 
about 600 pounds of coal per day, and as the coal cost $9.50 per 
ton delivered in the field, the saving soon paid for the expense 
of the test. Points of adjustment are provided on all valve 
gears, and as they differ in detail for each engine we cannot 
give explicit directions for settling the valves, but will leave 
this point for the direction book of the maker. 

The governor and governor belt should now receive atten- 
tion making sure that there are no loose points or nuts in the 
mechanism and that the governor belt is in good condition. 
Defective governor belts are dangerous through the possibility 
of over speeding. Slipping or oily belts not only increase the 
chances of fly-wheel explosions, but also cause a fluctuation 
in the speed which is not desirable especially in threshing, 
where good results are obtained only by a constant speed. 
Make sure that the safety lever works properly and shuts off 
the steam with a loose or broken belt. Test the governor valve 
stem for sticking or for rough shots that are likely to cause 
uneven running. Keep the governor well lubricated with light 
oil, and keep the oil off the belt as much as possible. Governor 
valve should be carefully tested for tightness and freedom. 

The throttle valve must be absolutely steam tight for a leak- 
ing valve is a dangerous proposition especially in stopping the 



GAS, OIL AND STEAM ENGINES 36] 

engine. It is generally arranged so that it can be regrdund 
with pumice stone or crocus powder and oil. If the valve is of 
bronze or brass do not use emery or carborundum for the par- 
ticles will become imbedded in the soft metal and put it in a 
worse condition than ever. Pack the valve stem. 

A leaking slide valve is the cause of much loss of power, and 
waste of coal, and as the leakage mingles directly with the 
exhaust, it often remains unknown until it has thrown away 
a considerable quantity of fuel. It is best detected by block- 
ing the engine with the piston at mid-stroke and opening the 
throttle valve slightly. If the cylinder drain cocks are now 
opened, the leaking steam that escapes into the cylinder will 
be seen issuing from the drains. The leakage that passes into 
the exhaust will be seen escaping from the stack while it is 
practically impossible to have the valves absolutely tight at 
all times, the steam should not escape so rapidly that it roars 
through the openings. Leakage past the piston is another 
source of loss that can be detected by blocking the engine so 
that the piston is very near, one end of the stroke, with the 
valve opening one of the cylinder ports. Any steam that passes 
the piston will pass out of the exhaust. With an old engine it 
is likely that the cylinder is worn oval, or that the valve seat 
is grooved or uneven, in which case it will be necessary to 
rebore the cylinder and fit new piston rings or reface the valve 
seat. Broken piston rings are often the source of leakage, and 
if not replaced with new at an early date, are likely to destroy 
the cylinder bore as well. Broken rings generally make them- 
selves known by a wmeezing click when the engine is running. 

The steam feed pump should be well lubricated with a good 
grade of cylinder oil and should be well packed around the 
piston rod especially at the water end. To guard against pump 
troubles a good strainer should be provided on the water suc- 
tion line to prevent the entrance of sticks and dirt into the 
cylinder. Great care should be exercised in keeping the suction 
line air tight, for if any air escapes into this line no water will 
be lifted. Dirt under the valves is the cause of much pump 
trouble, as a very small particle of dirt will allow the water 
to pass in both directions through the valves. Leaking pack- 
ing will also destroy the vacuum in one end of the cylinder. 
For the best results the pump should be run slowly but con- 
tinuously, feeding a small amount of water at one time. This 
method of feeding allows the feed water heater to bring the 
water up to the highest possible temperature which reduces the 



362 GAS, OIL AND STEAM ENGINES 

fuel consumption and reduces the strains on the boiler. It is a 
bad policy to let the water get low in the boiler and then ''ram" 
full of cold water in a couple of minutes. Attention should be 
paid to the check valve that is located between the pump and 
boiler. It should be kept clean and the valve kept tight and 
in good condition. 

When the feed water is hard a boiler compound should be 
used to reduce the amount of scale in the boiler or soften it 
and make its removal easier. Scale of 1/16 inch thickness will 
decrease the efficiency of the boiler by 12%, and this loss in 
creases rapidly with a further increase in the thickness of the 
scale because of its insulating effect on the tubes. Soft sludges 
such as mud and clay may be removed by -blowing off or by 




Buffalo Marine Motor. 

the filtration of the water before it is pumped into the boiled. 
Lime and magnesia which form flint-hard deposits, require 
chemical treatment such as the addition of sodium phosphate, 
etc. In any case, the deposits waste heat and increase the lia- 
bility of burning out tubes or bagging the sheets. 

A solution that has given good results with waters containing 
lime, consists of 50 pounds of Sal Soda and 35 pounds of 
japonica, dissolved in 50 gallons of boiling water. About 1/40 
quart is fed into the boiler for every horse-power in 10 hours, 
the solution being mixed with the feed water. Kerosene has 
been used a great deal to soften scale, and gives good results 
if not fed in quantities to exceed 0.01 quart per horse-power 
day of 10 hours. An excess of kerosene is to be guarded against 
for it is likely to accumulate in spots and cause bagged sheets 
or burn outs. 



CHAPTER XV. 
OIL BURNERS. 

(156) Combustion. 

To obtain the full heat value of a liquid fuel it must be pro- 
vided with sufficient air to complete the combustion, it must 
be in a very finely subdivided state, or in the form of a vapor 
at the time of ignition, and it must be thoroughly mixed with 
the air so that every part of the oil is in contact which its 
chemical equivalent of oxygen. Failure to comply with any of 
these conditions will not only result in a waste of fuel but will 
also be the cause of troublesome carbon deposits and soot, 
which eventually will interfere with the operation of the burner. 

Complete combustion is much more easily attained with the 
lighter hydrocarbons such as gasoline or naptha than with 
crude oil or the heavier distillates, for they are more readily 
vaporized and mix more thoroughly with the oxygen. Only a 
slight degree of heat and pressure is required with gasoline 
while with crude oil a high atomizing pressure and high tem- 
perature are required to obtain a satisfactory flame. In the 
majority of cases where heavy oils are used the fuel is not 
even completely vaporized but enters the combustion chamber 
in the form of a more or less finely atomized spray. The meth- 
ods by which the liquid fuel is broken up divides the burners into 
three primary classes. 

(1) LOW PRESSURE BURNERS in which the fuel is 
atomized by a blast of low pressure air which also supplies a 
considerable percentage of the air required for combustion. 

(2) HIGH PRESSURE BURNER in which a small jet of 
high pressure air or steam is used to atomize the oil, the air 
for combustion being supplied from a source external to the 
burner. 

(3) COMBINED HIGH AND LOW PRESSURE BURNER 
in which the fuel is atomized by high pressure air or steam, 
and the greater part of the air for combustion is furnished by 
a blower at a comparatively low pressure. 

In class (1) the oil is supplied to the burner under pressure 

363 



364 GAS, OIL AND STEAM ENGINES 

4 

and by means of a specially designed jet is thrown against 
hot baffle plates or gauze screens where the partially broken 
up liquid is caught by the high velocity air and reduced to a still 
liner spray by its impact against other screens or baffles fur- 
ther on in the burner. This system is applicable only to the 
light and intermediate grades of oils, such as gasoline, naptha 
or kerosene, unless heat is applied to the external casing to aid 
in the vaporization. In some cases the projection of the burner 
into the furnace gives satisfactory results, but with such an 
arrangement there is a tendency to deposit carbon in the bur- 
ner and for the flame to "strike back" should the velocity of 
the air fall below a certain critical point. Better results were 
had with this type of burner, by the author when the air blast 
was preheated by passing several long lengths of the intake 
air pipe over a hot part of the furnace, instead of entering the 
burner nozzle into the combustion chamber proper. 

A well known modification of this type is the gasoline torch 
used by electricians and plumbers in which the gasoline is 
sprayed into a perforated hot tube by air pressure in the tank. 
When the spray formed at the needle valve strikes the sur- 
rounding hot tube it is instantly vaporized and is mixed with 
the air passing through the perforations in the tube. While 
the air entering the tube is not forced through the openings 
by external pressure it attains sufficient velocity to aid in the 
vaporization because of the vacuum established by the jet. 
This however is only enough for the more volatile fuels — such 
as gasoline or benzine. 

The high pressure which is by far the most commonly used 
with low grade fuels may be divided into five principal types 
(a) ATOMIZER burner, (b) The INJECTOR burner, (c) 
DRIP feed burner, (d) CHAMBER OR INTERNAL burner, 
(e) EXTERNAL BLAST burner. All of these burners break 
up the fuel by high pressure air or steam, the types given be- 
ing different only in the way that the pressure is applied to 
the fuel. 

The atomizer acts on the same principle as the medical or 
perfumery atomizer, the high pressure jet playing directly across 
the open end of the oil passage as shown by Fig. A. As 
the vacuum created by the blast is very low, and has little ef- 
fect in lifting the fuel to the burner, the oil either is made 
to flow by gravity or by a pump. In the figure the oil in the 
upper passage is shown pouring down in front of the air or 
steam jet issuing from the lower port. Both ports are supplied 



(JAS, OIL AND STEAM ENGINES 



365 



by the pipes shown by the circular openings at the right. The 
steam and oil are controlled by independent valves placed in 
the two passages. 

In practice the oil and steam openings at the end of the 
burner may be either single or multiple round openings or long 
thin slots, the former style being the most common. Since 
only a small amount of air is admitted through the blast 
nozzle, far too little to completely consume the oil, the air 



O/L 




Fig. 135. Showing the Different Classes of Oil Burners. 

for the combustion is admitted through openings in the com- 
bustion chamber proper, this air being supplied by natural draft 
or by blower. In some cases the burner is entered into the fur- 
nace through an opening that is much larger than the burner 
itself. The atmospheric air enters through baffle plates in this 
opening- which impart a whirling motion to the air that passes 
over the burner. This is of considerable aid in maintaining 
complete combustion in the furnace, and also tends to prevent 
deposits in the burner. 



366 



GAS, OIL AND STEAM ENGINES 



In the injector type of burner shown by Fig. B the air or 
steam nozzle terminates inside of a shell and is completely sur- 
rounded by the oil. A mixture of air and oil issues from main 
nozzle shown by (2). When the air or steam blows through 
the inner opening, a partial vacuum is formed in the space (1) 




Fig. F. 



Mixed Pressure Burner, Using Both Steam and Low Pressure 
Air. 



which draws the oil into the burner from the supply pipe. On 
entering this vacuous space the oil comes into contact with 
the jet and is blown out through the opening (2) in the form 
of a spray. This vacuum is high enough to lift the fuel for a 
considerable, distance without the aid of a pump and for this 
reason is the type most commonly met with in practice. A 




Fig. G. Burner Used by the Pennsylvania Railroad Under Locomotives. 

boiler or furnace equipped with this burner will lift the oil 
directly to the furnace from the reservoir in the same way that 
a feed water injector will lift water into the boiler. With the 
commercial injector, the position of the steam jet is made 
adjustable in relation to the main jet to meet different feed 
conditions. The steam enters the inner port through the end 



GAS, OIL AND STEAM ENGINES 



367 



of the pipe shown at the right. The oil enters the outer port 
at the right through a port not shown. 

Fig. C shows a drip feed or "dribbling" burner in which the 
oil pours out of the upper port and over the lower port through 




Fig. H. Lassoe-Lovelsin Burner. 



which the steam or air issues. As would be expected, the 
atomization is not as perfect with this burner as with the 
atomizer or injector type. 

A burner in which the oil and steam mix before passing out 
into the furnace through the final opening is known as a "Cham- 




Sheedy Oil Burner, Used for Locomotives. 



ber burner," and is shown by Fig. D. In some respects, at 
least in construction, it is similar to the injector burner, but 
it does not possess the lifting abilities of the latter because 
of the open space in front of the stea^m nozzle. The atomiza- 



368 GAS, OIL AND STEAM ENGINES 

tion takes place largely within the burner because of the eddy 
currents of air and oil vapor created both by the vapor strik- 
ing the walls of the outer tube and by the large space in which 
it has to circulate before passing out of the orifice. 

An external blast burner as shown by Fig. E, in which the 
oil is forced out of the openings (3-3) at the extreme end of 
the burner atomizes by blowing the oil oft" of the tube by jets 
of steam directed by a series of annular openings in a disc. 
This is really a type of atomizer burner as will be seen by close 
inspection. This type must be very carefully constructed and 
the steam jets must be kept very clean in order to have good 
results for a little variation in the pressure or a small particle 
of dirt in the openings will deflect the steam and prevent a 




perfect oil spray. It's one advantage lies in the fact that the 
oil and air are always separate and therefore miminize the danger 
of carbonization. 

It should be noted that the figures just shown in the illus- 
tration of the various classes of burners are diagrammatic only, 
and that many modifications in detail are made in the practical 
burner such as regulating valves, sliding steam nozzles, etc. 

A burner much used in stationary engine practice and with 
heating furnaces, where air at two or three ounces pressure 
is available, is the mixed pressure burner shown by Fig. F. In 
this burner* steam or air compressed, to say 80 pounds per 
square inch is used for breaking up the fuel oil. A blast of 
air at low pressure but with considerable volume is used to 
support combustion in the furnace. The steam or compressed 
air enters the burner at (5) and meets the oil at the nozzle (8) 
where it is sprayed into the chamber (9). The oil enters the 
burner by the pipe (4), flows into the annular passage around 



GAS, OIL AND STEAM ENGINES 369 

the steam nozzle and meets the steam at (8). It will be noted 
that the steam nozzle (5) is free to slide back and forth in its 
casing so that the relation between the steam nozzle and spray 
nozzle may be adjusted to meet different operating conditions. 
This adjustment is affected by the levers (1U) at the end of 
the burner. 

The low pressure air entering thiough opening (6) from the 
blower passes around the chamber (9) and mixes with the oil 
spray from (8) in the mixing chamber (7). This causes a 
violent swirl in (7) with the result that a comparatively inti- 
mate mixture of oil vapor and air is formed before they issue 
into the furnace. In many burners of this type a gauze screen 
(11) is placed over the mouth of the final orifice so that back 
fires are prevented and a still better mixture is formed. Many 
burners of this type have been built by the author with very 
satisfactory results, and he knows of only one weak point in 
the type. This is due to the fact that if a sufficient volume of 
air is not kept flowing through the low pressure pipe (6), the 
oil vapor may collect in the piping with the result a back fire 
will wreck all of the low pressure connections. To prevent 
this trouble a light galvanized iron weighted damper was placed 
beneath (6) which closed the pipe when the pressure fell be- 
low a certain amount. Since this check valve was placed there 
were no more pipe fires. 

In all cases a sliding damper should be placed in the open- 
ing so that the blast can be regulated to suit the amount of oil 
injected. 

As these burners were used in a closed building continuously 
without smoke or smell and with indifferent grade of oil it will 
be seen that the combustion was as nearly perfect as could be 
expected with any type of oil burner. 

Several of these burners were made from ordinary steam pipe 
fittings without steam nozzle adjustment. 

While the burners shown are arranged to give a flat flame 
(with the exception of burner F) they may all be built for a 
circular flame by surrounding the injection nozzle with a suit- 
able nozzle. • A ROSE or circular flame is particularly desir- 
able for a vertical boiler where it can be made to conform 
with the circular shell and apply the heat directly to the tube 
sheet through suitable fire brick baffles. 

A burner of the injector type shown by Fig. G, has been 
used by the Pennsylvania Railroad with a considerable degree 
of success. The steam enters the steam nozzle at (12) through 



370 GAS, OIL AND STEAM ENGINES 

the circular openings from which point it passes through the 
nozzle (13) and carries the oil from the air port (14). The 
mixture or spray of steam and oil passes out of the nozzle 
(15) into the furnace. The steam nozzle is threaded into the 
casing at (16), and is keyed to the bevel gear (17). Meshing 
with (17) is the bevel mounted on the vertical stem which 
terminates in a hand-wheel in the engineer's cab. By turn- 
ing the bevels, the nozzle turns in the casing threads causing 
it to move back and forth for the adjustment. 

In many types of burners having a nozzle similar to (15) a 
twisted form of rifling is placed in the bore that gives the 
escaping gas a rotary motion. This is very effective in mix- 
ing the air and oil vapor and spreads the flame very close to the 
orifice. In burners of the chamber type a spiral vane is some- 
times used to gain the same effect, and in one make a rotating 
fan, is placed near the opening of the outer nozzle which gives 
a sudden whirl to the gases. While this latter attachment does 
all that is claimed for it while it is in good repair, it is very 
likely to stick and put the burner out of commission. 

The Lassoe-Lovekin locomotive burner is shown by Fig. H 
in which the gas exits through a^ series of holes in the end of 
the nozzle (22). The steam enters the outside casing, and 
unlike the burners just described, entirely surrounds the cen- 
tral oil nozzle, (20). The steam in passing through the open- 
ings 21-22 draws the oil through the central opening (23), this 
oil nozzle being controlled by the needle valve (24) which termi- 
nates in the handle (25). Oil enters the oil nozzle through the 
inlet pipe (26). 

The Sheedy oil burner shown by Fig. I has a rectangular 
nozzle for a flat flame, and has no steam nozzle adjustment. 
Oil surrounds the steam nozzle and enters the casing through 
the upper connection. Air enters the lower port through the 
lower opening as shown in the' cross-section of the burner. As 
the oil flows over the trough formed by the steam nozzle it 
meets the jet of steam at (30) and is atomized. The air from 
the lower port aids in bringing the combustion near the tip 
of the nozzle and therefore prevents carbon deposits from be- 
ing formed in the burner as well as spreading the flame at a 
wide angle. 



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Common Battery Systems 

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Primary and Storage Cells 

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Modern Battery Systems — 

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Low Tension Magnetos — Low tension magnetos 
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Gnome Rotary Motor. Ford Car Ignition Sys- 
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Self- Starting and Lighting — Circuit diagrams 
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AUTOMOBILE DRIVING SELF-TAUGHT 

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''Ignition, Timing and Valve Setting,** 'Automobile Motors 
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Automobile Driving— Gen. 
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5 K^ ^ *>£3$i&Jt3 Clutch— The Control levers— Prin- 
c ^sfet^^§^S5% ciples of gear changing— The en- 
gine as a factor— Use of biakes— 
Causes of irregular firing— To 
avoid sideslip— The tire bill— Gear 
missing in speed changes— Engine 
thumping— Driving on the brake 
—How to get the best work out of 
a motor— Skidding or side-slip. 

Self-tuition in driving Continued— The initial trip 
—Charging tanks— Starting the engine— Manipulating the 
control— Correct mixture— Changing gear— On the top speed 
—Withdrawing the clutch— Coasting slopes— Picking up 
the Drive — Driving on the reverse— Entering and leaving the 
garage— After the drive — Road risks. ft 

Another lesson in driving— Learning the steering and 
Control— Preliminary attention to car — Starting— Changing 
Speed — Coasting, braking and reversing — Sources of side- 
slip—To avoid skidding— Non-slip devices— Choice of Track- 
Speed limits— Conduct in emergencies— Driving through city 
traffic— Meeting horses, cattle and cyclists. 
Difficulty in starting— Symptoms,causes and remedies. 
Involuntary stops— Causes and remedies. 
Loss of power— Causes and remedies. 
Care and maintenance of motor cars— Private 
housing— The garage— Cleaning— Lubricating— Care of tires. 
Care of a car on a tour— Engine treatment— Overhaul- 
ing the ignition apparatus— Accessories and tools for the 
tour— Stabling the car. 

Layingupac ar— Cleaning the engine— The transmission 
gear— Connections and chains— The lubricators— Tire treat* 
ment— Laying up for the winter. 

Gasolene— Its properties and Economical Use— Produc- 
tion of Gasolene— Its distillation— Specific gravity— Vaporiza- 
tion experiments— Proper design and function of the car- 
bureter—The ton mileage Method of arriving at economy- 
Quality of the tuel. 
Gasolene hints and tips. 
Operating mechanism of a modern car* 
Choice of a car. Etc.- Considerations of price and cost 
of maintenance— Small and large cars— New and tried types- 
Second hand cars. 

Change speed gear— Various forms— Selective sliding 
gears— The Panhardand Mercedes systems— Gate control 
mechanism, etc. 
Don ■ ts for motor ca' drivers and tire owners* 

PriC£ FLEXIBLE LEATHER - $1 50 



CLOTH BINDING 



$1 

1 



00 




Gas Engine Troubles and Installation 

By J. B. RATHBUN, B. S. C. E. 

Author <A "Commercial Vehicles for AH Purpoact," 
"Oxygen— Acetylene Welding," etc 

420 Pages, 150 Detailed Line Drawings and Illustrations. 

•J A book that shows yoa HOW TO INSTALL- 
HOW TO OPERATE-HOW TO MAKE IMMEM 
ATE REPAIRS and HOW TO KEEP A GASOLEKB 
ENGINE RUNNING. The language Is simple 
—The Illustrations are dear, The book le 
authentic— complete — up - to • the - minute, 
written by an expert who Is employed daRr 
as a Consulting and Demonstrating Engineer 
and Instructor. Nothing has been omitted 
—it contains no useless matter— Just the 
cream of daily experience. Two Folding 
Trouble Charts, 

CONTENTS 

Elementary mechanics— Units of heat and mechanics defined 
— »Fuel3— Behavior of gases under the influence of heat and 
pressure — Combustion— Work done by the expansion of gasea 
— Composition of the charge— The elementary gas engine- 
Functions of the cylinder, piston connections, rod and crank 
— -Cycle defined—- Pour stroke cycle, two stroke cycle, six 
Btroke cycle defined— Functions of ports, valves, and cams 
Bs applied to foregoing types — Events in cycles— Periods of 
IgnitionQcompression, etc., outlined — Multiple cylinder 
engines— Crank relations— Ignition— Flame, catalytic, hot 
tube, electric (high and low tension)— Make and break ignl- 
Hon— Batteries— Spark coils, dynamos— Magnetos— Wiring 
systems— Timing— discussion of prominent makes of ignition 
apparatus— Valve gears— Practical construction of valves 
and valve operating mechanism— Valve timing charts— 
Location of ports in two stroke cycle engines— Three port, 
two-stroke cycle engines — Mixing valves — Carburators — 
Manifolds for multi-cylinder engines— Mufflers— Exhaust 
pots, etc.— Cooling systems— Purpose of cooling systems— 
The radiator— Air cooling— Tank, hopper and trays— Circu- 
lating pumps — Thermo — Syphon — Water vs. oil — Anti- 
freezing solutions— Lubrication— Splash, force feed, exhaust 
feed, properties of lubricat ng oils, grease, pumps, strainers, 
filters, cups, connections, etc.— Details of approved systems. 
—Construction details— En gines for various purposes— Elec- 
tric lighting engines— Dynamos— Storage batteries— Wiring— 
Switcn Board— Installaton — Engine room arrangement- 
Foundations— Piping— Shafting— Hangers, etc. — Operation— 
Trouble Chart for location of troubles— Remedies for troubld 
—Shop rules— Formulas— Automobile, motor boat and aero 
motors. Trouble Chart— Accessories— Operation, etc.. etc 

FLEXIBLE LEATHER $1 .60 
CLOTH BINDNIQ - - 1.00 



Price, 




THE PRACTICAL HANDBOOK OF GAS, 
OIL, AND STEAM ENGINES 

BY JOHN B. RATHBUN. 

Author of "Gas Engine Troubles 
and Installation," Editor "Igni- 
tion" — Instructor Chicago 
Technical College. 
370 Pages, 150 Line Drawing I 
sad Illustrations. 
This book is the most complete 
and up-to-the-minute book for the 
practical man on the subjects of 
gas, gasoline, oil, and steam engines 
Oil burners for use in steam engines 
13 a useful feature. Special empha- 
sis is placed on farm tractors and 
their operation, both oil and steam 
driven. The engines described are 
the latest types, and include the 
Diesel, Semi -Diesel Gnome, Low 
and turbine types. 

CONTENTS 

Heat and Power. — Fuels — Calorific Values of Fuels- 
Solid, Liquid and Gaseous Fuels — Kerosene — Gasoline- 
Crude Oil — Producer Gas — Illuminating Gas — Coal — 
Benzol. Working Cycles — Definitions of Cycles 
Indicator Diagrams — Practical Use of the Indicator — 

Typical Four Stroke Cycle Engines — Single Cylinder 
— Four Cylinder — Automobile — I Opposed Type — 
V Type — Tandem— Twin Tandem — Rotary Cylinder — 
Radial — Diesel — Knight — Argyle — Rotary Valve. Typi- 
cal Two Stroke Cycle Engines— Two Port— Three Port- 
Marine — Controlled Port — Aeronautic — Oechehauser— 
Gnome Rotary Two Stroke. Oil Engines — Elyria — Marine 
Diesel — Installation — Aspiration Types — Fairbanks Morse 
— Kerosene — Carburetion — Semi-Diesel — Combustion of 
Heavy Oils. Ignition Systems — Hot Tube System — Low 
Tension System— High Tension System — Details of Make- 
and-Break Batteries — Low Tension Magnetos — High Ten- 
sion Magnetos — C oil s — Adjustment — Troubles. Carbu- 
retors — Principles of Carburetion — Jet Carburetors — 
Water Jacketing — Fuel Supply — Different Types of Auto 
Carburetors — Adjustment — Carburetor Troubles. Lubri- 
cation — Forced Speed — Splash System — Oil Pumps — 
Lubrication Troubles. Cooling Systems — Evaporation 
Systems — Radiators — Air Cooling. Speed Governors — 
Automobiles — Stationary — Adjustment — Mixture — Control 
Hit and Miss — Mixed Systems. Tractors and Various 
Farm Engines — Gasoline and Oil Tractors — Mechanism 
of Various Types — Steam Tractors — Plowing and Thresh- 
ing Costs — Plowing Contests Data — Two Speed Mechan- 
isms — Draw Bar Pole — Oil Carburetors, etc. Oil Burn- 
ers — Combustion — High Pressure System — Low Pressure 
System — Mixed System — Burners for Furnaces, Locomo- 
tives, Pennsylvania Type, Sheedy Burner, Kirchoff 
Burner, etc. 
DDI/T J Flexible Leather • • • $1.60 

rKltt: 1 siikcioth 1.00 



Questions and Answers 
For Automobile Students and Mechanics 



QUESTIONS $ ANSWERS 

i^UT0M0BILESlUDENT5i| 
^) and MECHANICS CZ 




-By- 

Thomas H. Russell. A.M.. ME. 

Author of "Automobile Driving 
Self -Taught," "Automobile 
Motors and Mechanism " "Ig* 
nition. Timing and Valve Set* 
ling." "Motor Boats: Construe* 
fjoo and Operation/* etc.. etc 



A book of 600 Questions and 
Answers, adapted for teaching 
School, the Machlneshop or be- 
fore the Board of Examining 
Engineers. This Is the largest, 
the latest and most authentic 
book of Its kind upon the market. Prepared especially for 
Home Study. 150 pages. Bound In Cloth, Stiff Covers 
-In fact It Is a regular text book. 



The Questions and Answers in this book will 
be found useful by every Student and Mechanic 
of Motor Cars and Motoring, as a handy means of 
reviewing systematic study or in daily work. 

It has long been recognized that the Question 
and Answer method is most effective in fixing 
in the memory facts gained by study or problems 
that confront the Mechanic in his daily work; 
hence it is adapted for the purpose. 

The more important subjects connected with 
Motor Cars, are treated individually, there being 
a separate set of Questions and Answers for 
each. For the greater convenience of the reader, 
the Questions and the Answers in each set appear 
on separate pages; the Questions can thus be* 
used alone for self-instruction, while the Answers 
if needed are close at hand for reference. 

Minor subjects are covered in a special Cate- 
chism, which deals with all the factors which go 
to make up the power plant of a Modern Motor 
Car. 

PRICE, Cloth... $1.00 Leather... $1.50 




AUTOMOBILE MOTORS AND MECHANISM 

By THOMAS H. RUSSELL. M. E., LL. B. Author of 

Automobile Driving Self -Taught, Ignition, Timing and 

Valve Setting. Motor Boats: ConrtructionandOperation/'etc 

Pocket size, 265 pages, Blue flexible 
l eather, r ound corners, red edges, fully 
illustrated 

CONTENTS 

The Internal Combustion Engine 

—Principles and Construc- 
tion—Production of the fuel 
mixture—Function of the 
carbureter — The cycle of 
operations — Cylinders, pis- 
ton and rings — Shafts and 
bearings — Ignition appara- 
tus — Single and multi-cylin- 
der engines — The two cycle 
engine — Valves and their 
functions — Silencing the exhaust — Engine hints 
and tips—A Typical Modern Motor— Detailed de- 
scription of construction — Governing and Governors 
—The centifrugal governer — Throttle valves— 
Governing and control — The hit-or-miss gover- 
nor — Carbureters — The float-feed principle — The 
float chamber and jet — Various types of modern 
construction— Quality of mixture — Flooding the 
carbureter — Carbureter troubles and adjust- 
ments, etc. — Transmission Mechanism — The Clutch- 
Various forms in use — Positive and friction 
clutches — Plate or disk clutches — The combined 
disk and cone type — Expanding clutches — Clutch 
troubles, etc. — Gear or Gearing— Belt and chain 
gearing— Friction gear — Spur or tooth gearing 
— Spiral, helical, worm and bevel gearing— 
Epicyclic gear— Infinitely variable gear — Differen- 
tial or Balance Gear— Its functions— Shafts and their 
Functions — The crankshaft, half-speed shaft, 
countershaft, etc.— Lubrication and Lubricators- 
Pumps and their Purposes — Motor Misfiring, Causes and 
Remedies— Noises in the Motor, Causes and Remedies — 
Motor Overheating, Causes and Remedies— Electric Mot- 
ors — Principles and operation — Steam Cars — The 
engine,, generator, reverse gear, etc, 

DhiGP FLEXIBLE LEATHER - $1.50 
r 1 1W-W} CLOTH BINDING - - 100 



ABC 

of the MOTORCYCLE, 

By W. J. JACKMAN. M. E. Author of 
Facu for Motorists, ' * * 'Crushed Stone and 
Its Uses," and Similar Bookt. 

Pocket Size, 250 pages, 
fully Illustrated, Leather 
and Cloth, Round Cor- 
ners, Red Edges. A 
"Show How" Book for 
Owners and Operators of 
Motorcycles. 

CONTENTS 
Inception and Evolution of 
the Motorcycle — Modern 
Machines and their Vital 
Parts — How to Master the 
Mechanism — Production and Application of Mo- 
tive Power — Construction and Operation of the 
Carbureter— What the Carbureter Does— Ignition 
Systems — Batteries and Magnetos — Practical 
Methods of Handling — Various Types of Motors 
—Theory and Effect of Internal Combustion — 
Troubles of all Kinds and How to Avoid or Over- 
come Them — Lubrication Methods — Transmis- 
sion or Drive Systems— How to Compute Horse 
Power — Relation of Power and Speed— Weather 
Effects on Gasolene Engines— Cost of Mainten- 
ance on Basis of Mileage — Some Dont's that will 
save Time and Money — Selecting a Motorcycle 
— Hints for the Buyer — What an Owner 
should do on receiving a New Machine — The 
First Ride. 




Price, 



FLEXIBLE LEATHER 
CLOTH BINDING - 



$1.60 
1.00 



DUSTMAN'S PLAN BOOK 

and 

COMPLETE MODERN ESTIMATOR of 
GENERAL BUILDING CONSTRUCTION 

By U. M. Dustman, Licensed Architect, 
Editor of "The Progressive Builder." 

250 pages, 9x13 inches, Several Books Combined in One. 
Invaluable to the Contractor, Builder or Layman. 



DUSTMAN'^ 



Book^Plans 

t- AND BUILDING CONSTRUCTION I dbawini 




Cloth Binding, White Foil Stamping, 

PRICE . . . $2.00 

CONTENTS 

Designs and Suggestions — Geometrical Problems Illus- 
trated — Roof Trusses Illustrated — Rafter Diagrams — 
Construction Diagrams — Stair Work Diagrams — Stair 
and Handrailing Tables — Window Frame Work and 
Diagrams — Store Front Problems Illustrated — Brick 
Work Construction and Tables — Window Frames for 
Brick Walls — General Construction Problems, Concrete 
Work, Arches, Brick Work, Mill Construction, Beams, 
Columns and Splices, Framing, Drafting, Properties of 
Woods and Metals— Plastering— Painting— Roofs— Tables 
of Mensuration — Engineering Tables of Beams, Columns, 
Channels, etc. — Tables of Rafters — Building Terms — 
Builders' Arithmetic — How to Read Plans — Detailed Es- 
timates of various mechanical departments — Complete 
Detailed Specifications Form — Concrete Mixing, Con- 
struction of Houses, Barns, Garages, Silos, Sidewalks, 
etc— Photographs, Plans and Elevations of Many 
Houses, Barns. Public Buildings, Out-buildings, etc. 



